As filed with the Securities and Exchange Commission on September 20, 2005

Registration No. 333-128045

UNITED STATES SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Amendment No. 1

to

Form F-9

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

THE THOMSON CORPORATION

(Exact name of Registrant as specified in its charter)

Metro Center, One Station Place

Stamford, Connecticut 06902

(203) 539-8000

(Address and telephone number of

Registrant’s principal executive offices)

Deirdre Stanley, Esq.

Thomson Holdings Inc.

Metro Center, One Station Place

Stamford, Connecticut 06902

(203) 539-8000

(Name, address (including zip code) and telephone number

(including area code) of agent for service in the United States)

Copy to:

Andrew J. Beck, Esq.

Torys LLP

237 Park Avenue

New York, New York 10017-3142

     Approximate date of commencement of proposed sale of the securities to the public: From time to time after the effective date of this Registration Statement.

Province of Ontario, Canada

(Principal jurisdiction regulating this offering)

     It is proposed that this filing shall become effective (check appropriate box):

     If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to the home jurisdiction’s shelf prospectus offering procedures, check the following box:    þ

     The Registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the Registration Statement shall become effective as provided in Rule 467 under the Securities Act of 1933 or on such date as the Commission, acting pursuant to Section 8(a) of the Act, may determine.

PART I

INFORMATION REQUIRED TO BE DELIVERED TO OFFEREES OR PURCHASERS

     This short form base shelf prospectus has been filed under legislation in each of the provinces of Canada that permits certain information about these securities to be determined after this prospectus has become final and that permits the omission from this prospectus of that information. The legislation requires the delivery to purchasers of a prospectus supplement containing the omitted information within a specified period of time after agreeing to purchase any of these securities.

     This prospectus is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted. No securities regulatory authority has expressed an opinion about these securities and it is an offence to claim otherwise.

SHORT FORM BASE SHELF PROSPECTUS

The Thomson Corporation

US$2,000,000,000

Debt Securities

(unsecured)

       We may from time to time issue one or more series of unsecured debt securities, which we refer to as Debt Securities, in an aggregate principal amount of up to US$2,000,000,000 (or the equivalent in other currencies) or, if any Debt Securities are issued at an original issue discount, such greater amount as shall result in an aggregate issue price of US$2,000,000,000 (or the equivalent in other currencies), during the 25 month period that this short form prospectus, including any amendments hereto, remains valid.

      We will provide the specific terms of the Debt Securities in supplements to this prospectus. You should read this prospectus and any applicable prospectus supplements carefully before you invest.

      THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE UNITED STATES SECURITIES AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION NOR HAS THE SECURITIES AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION PASSED UPON THE ACCURACY AND ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.

      We are permitted, under a multijurisdictional disclosure system adopted by the United States and Canada, to prepare this prospectus in accordance with Canadian disclosure requirements, which are different from those of the United States. We prepare our financial statements in accordance with Canadian generally accepted accounting principles, and our financial statements are subject to Canadian generally accepted auditing standards and Canadian and U.S. securities regulatory auditor independence standards. Our financial statements may not be comparable to financial statements of U.S. companies.

      Owning the Debt Securities may have tax consequences in both the United States and Canada. This prospectus and any applicable prospectus supplement may not describe these tax consequences fully. You should consult your own tax advisor with respect to your own particular circumstances and read the tax discussion in this prospectus and any applicable prospectus supplement.

      Your ability to enforce civil liabilities under U.S. federal securities laws may be affected adversely because we are incorporated under the laws of the Province of Ontario, Canada, some of our officers and directors and some of the experts named in this prospectus are residents of Canada and some of our assets and some of the assets of those officers, directors and experts may be located outside of the United States.

Table of Contents

ABOUT THIS PROSPECTUS

      In this prospectus, the words “we,” “us,” “our” and “our company” and other similar words are references to The Thomson Corporation and its consolidated subsidiaries unless the context requires otherwise. All references in this prospectus to “$” or “US$” are to U.S. dollars and “C$” are to Canadian dollars.

      This prospectus is part of a registration statement on Form F-9 relating to the Debt Securities that we filed with the U.S. Securities and Exchange Commission, or SEC. Under this “shelf” registration process, we may, from time to time, sell any combination of Debt Securities in one or more offerings up to an aggregate principal amount of US$2,000,000,000. This prospectus provides you with a general description of the Debt Securities that we may offer. Each time we sell Debt Securities under the registration statement, we will provide a prospectus supplement that will contain specific information about the terms of that offering of Debt Securities. The prospectus supplement may also add, update or change information contained in this prospectus. Before you invest, you should read both this prospectus and any applicable prospectus supplement together with additional information described under the heading “Where You Can Find More Information.” This prospectus does not contain all of the information contained in the registration statement, certain parts of which are omitted in accordance with the rules and regulations of the SEC. You should refer to the registration statement and the exhibits to the registration statement for further information with respect to our company and the Debt Securities.

      We prepare our consolidated financial statements in accordance with Canadian generally accepted accounting principles, or Canadian GAAP, which differs from U.S. generally accepted accounting principles, or U.S. GAAP. Therefore, our consolidated financial statements incorporated by reference in this prospectus, in any applicable prospectus supplement and in the documents incorporated by reference in this prospectus may not be comparable to financial statements prepared in accordance with U.S. GAAP. You should refer to the notes of our audited comparative consolidated financial statements for a discussion of the principal differences between our financial results calculated under Canadian GAAP and U.S. GAAP (and the corresponding notes for subsequent years). Unless otherwise indicated, financial information in this prospectus has been prepared in accordance with Canadian GAAP.

WHERE YOU CAN FIND MORE INFORMATION

      Information has been incorporated by reference in this prospectus from documents filed with the securities regulatory authorities in each of the provinces of Canada. Copies of the documents incorporated by reference in this prospectus may be obtained on request without charge from the Secretary, The Thomson Corporation, Suite 2706, Toronto Dominion Bank Tower, Toronto-Dominion Centre, Toronto, Ontario, M5K 1A1 (telephone no. (416) 360-8700). For the purpose of the Province of Québec, this simplified prospectus contains information to be completed by consulting the permanent information record. A copy of the permanent information record may be obtained from the Secretary of our company at the above-mentioned address and telephone number.

      You may also access our disclosure documents and any reports, statements or other information that we file with the securities regulatory authorities in each of the provinces of Canada through the Internet on the Canadian System for Electronic Document Analysis and Retrieval, which is commonly known by the acronym SEDAR and which may be accessed at www.sedar.com. SEDAR is the Canadian equivalent of the SEC’s Electronic Document Gathering and Retrieval System, which is commonly known by the acronym EDGAR and which may be accessed at www.sec.gov. In addition to our continuous disclosure obligations under the securities laws of the provinces of Canada, we are subject to the information requirements of the U.S. Securities Exchange Act of 1934 and, in accordance with the Exchange Act, file reports and other information with the SEC.

      You may read or obtain copies, at a fee, of any document we file with or furnish to the SEC at the SEC’s public reference room at Room 1580, 100 F Street, N.E., Washington, D.C. 20549. Please call the SEC at 1-800-SEC-0330 or access its website at www.sec.gov for further information on the public reference room. Our filings are also electronically available from the SEC’s EDGAR, as well as from commercial document retrieval services.

      You are invited to read and copy any reports, statements or other information that we file with the securities regulatory authorities in each of the provinces of Canada at their respective public reference rooms. Reports and other information about us should also be available for inspection at the offices of the Toronto Stock Exchange and the New York Stock Exchange. Under the multijurisdictional disclosure system adopted by the United States and Canada, we are permitted to incorporate by reference in this prospectus certain information we file with the SEC and the securities regulatory authorities in Canada, which means that we can disclose important information to you by referring you to those documents. Information incorporated by reference is an important part of this prospectus. Information incorporated by reference must be filed as exhibits to the registration statement on Form F-9 that we have filed with the SEC in connection with the Debt Securities.

DOCUMENTS INCORPORATED BY REFERENCE

      The following documents, which have been filed with the securities regulatory authorities in each of the provinces of Canada and filed with, or furnished to, the SEC, are specifically incorporated by reference in this prospectus:

      Any statement contained in a document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded for the purposes of this prospectus to the extent that a statement contained herein, or in any other subsequently filed document which also is or is deemed to be incorporated by reference herein, modifies or supersedes that statement. Any statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this prospectus.

      Any documents of the type referred to above, any material change reports (excluding confidential reports, if any), all updated interest coverage ratio information, as well as all prospectus supplements disclosing additional or updated information that we file with the securities regulatory authorities in Canada after the date of this prospectus and prior to the termination of the distribution of Debt Securities shall be deemed to be incorporated by reference into this prospectus. To the extent that any document or information incorporated by reference into this prospectus is included in a report that is filed with or furnished to the SEC on Form 40-F or 6-K (or any respective successor form), such document or information shall also be deemed to be incorporated by reference as an exhibit to the registration statement of which this prospectus forms a part.

      A prospectus supplement containing the specific terms of any Debt Securities will be delivered, together with this prospectus, to purchasers of such Debt Securities and will be deemed to be incorporated into this prospectus for the purposes of securities legislation as of the date of such prospectus supplement, but only for the purposes of the distribution of the Debt Securities to which such prospectus supplement pertains.

      When we file a new annual information form and the related audited comparative consolidated financial statements with, and where required, they are accepted by, the applicable securities regulatory authorities during the time that this prospectus is valid, the previous annual information form, the previous audited comparative consolidated financial statements and all unaudited comparative consolidated financial statements, material change reports and information circulars filed prior to the commencement of our financial year in which the new annual information form is filed will be deemed no longer to be incorporated by reference into this prospectus for purposes of future offers and sales of Debt Securities under this prospectus.

      You should rely only on the information contained in or incorporated by reference in this prospectus or any applicable prospectus supplement and on the other information included in the registration statement of which this prospectus forms a part. We have not authorized anyone to provide you with different or additional information. We are not making an offer of Debt Securities in any jurisdiction where the offer is not permitted by law. You should not assume that the information contained in or incorporated by reference in this prospectus or any applicable prospectus supplement is accurate as of any date other than the date on the front of the applicable prospectus supplement.

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

      Some statements included and incorporated by reference in this prospectus constitute forward-looking statements. The words “anticipate,” “believe,” “plan,” “estimate,” “expect,” “intend,” “will,” “may” and “should” and similar expressions, as they relate to us or our management, are intended to identify forward-looking statements. These forward-looking statements are not historical facts but reflect our current expectations concerning future results and events. These forward-looking statements are subject to a number of risks and uncertainties that could cause actual results or events to differ materially from current expectations, which include, but are not limited to:

      These factors and other risk factors described in some of the documents incorporated by reference in this prospectus are not necessarily all of the important factors that could cause actual results to differ materially from those expressed in our forward-looking statements. We caution you not to place undue reliance on these forward-looking statements that reflect our view only as of the date of this prospectus. We disclaim any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

RISK FACTORS

      Investing in the Debt Securities is subject to certain risks. Before purchasing Debt Securities, you should consider carefully the risk factors set forth below and those under the heading “Risk Factors” in our annual information form, which is contained in our annual report on Form 40-F for the year ended December 31, 2004 (and our annual information forms for subsequent years), as well as the other information contained in and incorporated by reference in this prospectus (including subsequently filed documents incorporated by reference) and, if applicable, those described in the applicable prospectus supplement. If any event arising from these risks occurs, our business, prospects, financial condition, results of operation and cash flows could be materially and adversely affected.

Fluctuations in exchange rates could give rise to foreign currency exposure.

      Debt Securities denominated or payable in foreign currencies may entail significant risks, and the extent and nature of such risks change continuously. These risks include, without limitation, the possibility of significant fluctuations in the foreign currency market, the imposition or modification of foreign exchange controls and potential illiquidity in the secondary market. These risks will vary depending on the currency or currencies involved. Prospective purchasers should consult their own financial and legal advisors as to the risks entailed in an investment in Debt Securities denominated in currencies other than the local currency. Debt Securities are not an appropriate investment for investors who are unsophisticated with respect to foreign currency transactions.

Credit ratings assigned to Debt Securities may change.

      We cannot assure you that any credit rating, if any, assigned to Debt Securities issued hereunder will remain in effect for any given period of time or that any rating will not be lowered or withdrawn entirely by the relevant rating agency. A lowering or withdrawal of such rating may have an adverse effect on the market value of the Debt Securities.

There may not be a trading market for the Debt Securities.

      There is currently no market through which the Debt Securities may be sold. We cannot assure you that a secondary market for trading in the Debt Securities will develop or that any secondary market which does develop will continue.

The Debt Securities will be subordinated to creditors of our subsidiaries.

      We conduct our operations through a number of subsidiaries and to the extent any such subsidiary has or incurs indebtedness with a third party, the holders of the Debt Securities will effectively be subordinated to the claims of the holders of such third party indebtedness, including in the event of liquidation or upon a realization of the assets of any such subsidiary.

THE THOMSON CORPORATION

      The Thomson Corporation was incorporated under the Business Corporations Act (Ontario), Canada by articles of incorporation dated December 28, 1977. We restated our articles on February 28, 2005. Our registered office is at Suite 2706, Toronto Dominion Bank Tower, P.O. Box 24, Toronto-Dominion Centre, Toronto, Ontario, M5K 1A1. Our principal office in the United States is Metro Center, One Station Place, Stamford, Connecticut 06902.

OUR BUSINESS

      We are a global leader in providing integrated information solutions to business and professional customers. We organize our operations in four market groups that are structured on the basis of the customers they serve:

RECENT DEVELOPMENTS

      On August 2, 2005, we announced that we had exercised our right to redeem approximately US$400,000,000 of outstanding debt securities, consisting of all of our outstanding:

      We redeemed the privately-placed notes on August 16, 2005 and we redeemed the medium term notes on September 1, 2005. We anticipate that we will recognize a loss of approximately US$20 million in the third quarter of 2005 in connection with these redemptions.

      On August 9, 2005, we issued US$400,000,000 of 5.50% debentures due August 15, 2035.

USE OF PROCEEDS

      Unless otherwise specified in a prospectus supplement that accompanies this prospectus, the net proceeds from the sale of the Debt Securities will be added to our general funds and we will use them for general corporate purposes including to repay existing indebtedness. We may from time to time issue Debt Securities and incur additional indebtedness other than through an offering under this prospectus and any applicable prospectus supplements.

INTEREST COVERAGE

      After giving effect to our issuance on August 9, 2005 of US$400,000,000 aggregate principal amount of 5.50% debentures due 2035 and the use of the net proceeds from that offering, as if such offering occurred at the beginning of each period, the pro-forma interest, including these new debentures and other long-term and short-term debt for the 12 months ended December 31, 2004 and June 30, 2005, would amount to

US$242 million and US$231 million, respectively, for each such period. Our consolidated net earnings before deducting interest expense and other financing costs (including the effect of related debt swaps) and before income taxes for the 12 months ended December 31, 2004 were US$1,543 million, which is 6.38 times the pro-forma interest for that period, and for the 12 months ended June 30, 2005 were US$1,564 million, which is 6.77 times the pro-forma interest for that period.

      Excluding the results of discontinued operations, consolidated net earnings before deducting interest expense and other financing costs (including the effect of related debt swaps) and before income taxes for the 12 months ended December 31, 2004 were US$1,374 million, which is 5.68 times the pro-forma interest for that period, and for the 12 months ended June 30, 2005 were US$1,377 million, which is 5.96 times the pro-forma interest for that period.

      These coverage ratios do not give effect to the issuance of Debt Securities that may be issued pursuant to this prospectus.

SHARE CAPITAL

      Our authorized capital consists of an unlimited number of common shares and an unlimited number of preference shares without par value issuable in series. As of August 31, 2005, 653,114,196 common shares and 6,000,000 Series II cumulative redeemable floating rate preference shares were outstanding.

DESCRIPTION OF DEBT SECURITIES

      This section describes certain general terms and provisions of the Debt Securities. We will provide the particular terms and provisions of a series of Debt Securities and a description of how the general terms and provisions described below apply to that series in a prospectus supplement. Thus, for a description of the terms of a particular series of Debt Securities, you must refer to both the applicable prospectus supplement relating to that series and the description of the Debt Securities contained in this prospectus. In this section, the words “we,” “us,” “our” and “our company” refer only to The Thomson Corporation and not to any of our consolidated subsidiaries.

      Unless otherwise specified in a prospectus supplement, the Debt Securities will be issued under a trust indenture dated November 20, 2001, as amended and supplemented from time to time, between our company, Computershare Trust Company of Canada and Deutsche Bank Trust Company Americas. On September 20, 2005, we appointed Deutsche Bank Trust Company Americas as an additional Trustee under the trust indenture. We collectively refer to Computershare Trust Company of Canada and Deutsche Bank Trust Company Americas as the “Trustees” and each Trustee acting in such capacity for a specific series of Debt Securities as a “Trustee.” The trust indenture is subject to the provisions of Trust Indenture Legislation.

      This summary information does not purport to be complete and is qualified in its entirety by reference to the provisions of the Debt Securities and the trust indenture, including the definition of certain terms in the trust indenture. It is the trust indenture, and not this summary, that governs the rights of holders of Debt Securities. Capitalized terms that are used in this section and not defined have the meanings assigned to them in the trust indenture. We have defined selected terms at the end of this section. Section references below are to sections of the trust indenture.

      The trust indenture does not limit the amount of Debt Securities that may be issued under the trust indenture. The trust indenture provides that Debt Securities may be issued from time to time in one or more series and may be denominated and payable in U.S. dollars or any other currency. We may offer no more than US$2,000,000,000 (or the equivalent in non-U.S. Currency) aggregate principal amount of Debt Securities pursuant to this prospectus. The specific terms of any series of Debt Securities will be established at the time

of issuance and will be described in the applicable prospectus supplement. These terms may include, but are not limited to, any of the following:

      The trust indenture also provides that there may be more than one Trustee under the trust indenture, each with respect to one or more different series of Debt Securities. See “— Resignation of Trustee” below for more information. As there is more than one Trustee under the trust indenture, the powers and trust obligations of each Trustee as described in this prospectus shall extend only to the one or more series of Debt Securities for which it is Trustee. The Debt Securities (whether of one or more than one series) for which each Trustee is acting shall in effect be treated as if issued under separate trust indentures. The term “Debt Securities” as used in this prospectus shall mean the one or more series with respect to which each respective Trustee is acting.

      Some or all of the Debt Securities may be issued under the trust indenture as Original Issue Discount Securities (bearing no interest or interest at a rate that at the time of issuance is below market rates) to be issued at prices below their stated principal amounts.

      The general provisions of the trust indenture do not contain any provisions that would limit the ability of our company to incur indebtedness or that would afford Holders protection in the event of a highly leveraged or similar transaction involving our company.

      Under the trust indenture, we will have the ability, in addition to the ability to issue Debt Securities with terms different from those of other Debt Securities previously issued, without the consent of the Holders, to reopen a previous issue of a series of Debt Securities and issue additional Debt Securities of such series. (Section 301)

      The Debt Securities will be unsecured obligations of our company and will rank equally with all other unsecured and unsubordinated obligations of our company.

      Debt Securities of a series may be issuable solely as registered Debt Securities issuable in denominations of US$1,000 and integral multiples of US$1,000 or in such other denominations as may be provided for by the terms of the Debt Securities of any particular series. The trust indenture also provides that Debt Securities of a series may be issuable in global form, which we refer to as Global Securities. Debt Securities of any series will be exchangeable for other Debt Securities of the same series of any authorized denominations and of a like aggregate principal amount and tenor. (Section 305)

      The Debt Securities may be presented for exchange as described above, and Debt Securities may be presented for registration of transfer (duly endorsed or accompanied by a written instrument of transfer), at the corporate trust office of the Trustee or at the office of any transfer agent designated by our company for such purpose with respect to any series of Debt Securities. No service charge will be made for any transfer or exchange of Debt Securities, but we may require payment of a sum sufficient to cover any tax or other governmental charge payable in connection therewith. We may at any time designate one or more successor or additional transfer agents with respect to any series of Debt Securities and may from time to time rescind any such designation. (Section 305) We will be required to maintain a transfer agent in each Place of Payment for such series. (Section 1002)

      So long as required by the Business Corporations Act (Ontario), we shall cause to be kept, by our company or a trust corporation registered in Ontario, a central securities register that complies with the requirements of the Business Corporations Act (Ontario). Additionally, we will cause to be recorded promptly in the central securities register maintained pursuant to the Business Corporations Act (Ontario), the particulars of each issue, exchange or transfer of Debt Securities. Unless otherwise provided for in the case of any series of Debt Securities, the Trustee shall maintain at its corporate trust office a branch register containing the same information with respect to each entry contained therein as contained in the central register. In the event of a conflict between the information contained in the central register and the information contained in a branch register, the information contained in the central register shall prevail. (Section 305)

      We shall not be required to:

      The trust indenture provides, with respect to any series of Outstanding Debt Securities thereunder, that the following shall constitute Events of Default:

      No Event of Default provided with respect to a particular series of Debt Securities necessarily constitutes an Event of Default with respect to any other series of Debt Securities. (Section 501) We are required to file with the Trustee, annually, an Officer’s Certificate as to our compliance with all conditions and covenants under the trust indenture. (Section 1004) The trust indenture provides that the Trustee may withhold notice to the Holders of Debt Securities of any default (except payment defaults on the Debt Securities) if it considers it in the best interest of the Holders of Debt Securities to do so. (Section 502)

      If an Event of Default listed in clause (i), (ii), (iii), (iv) or (vi) of the second preceding paragraph with respect to Debt Securities of a particular series occurs and is continuing, the Trustee or the Holders of not less than 25% in principal amount of Outstanding Debt Securities of that series may declare the Outstanding Debt Securities of that series due and payable immediately. If an Event of Default listed in clause (v) of the preceding paragraph occurs and is continuing, then the Trustee or the Holders of not less than 25% in principal amount of all Debt Securities then Outstanding may declare the principal amount of all of the Outstanding Debt Securities to be due and payable immediately. However, in either case the Holders of a majority in principal amount of the Outstanding Debt Securities of that series, or of all Outstanding Debt Securities, as the case may be, by written notice to us and the Trustee, may, under certain circumstances, rescind and annul such declaration. (Section 503)

      Subject to the provisions relating to the duties of the Trustee, in case an Event of Default with respect to Debt Securities of any or all series occurs and is continuing, the Trustee shall be under no obligation to exercise any of its rights or powers under the trust indenture at the request, order or direction of any of the Holders of such Debt Securities, unless such Holders shall have offered to the Trustee reasonable indemnity against the expenses and liabilities which might be incurred by it in compliance with such request. (Section 508) Subject to such provisions for the indemnification of the Trustee, the Holders of not less than a majority in principal amount of the Outstanding Debt Securities of any series (with respect to any remedy, trust or power relating to or arising under an Event of Default described in clause (i), (ii), (iii), (iv) or (vi) above) or the Holders of a majority in principal amount of all Outstanding Debt Securities (with respect to any other remedy, trust or power), as the case may be, shall have the right to direct the time, method and place of conducting any proceeding for any remedy available to the Trustee under the trust indenture, or exercising any trust or power conferred on the Trustee. (Section 513)

      The Holders of not less than a majority in principal amount of the Outstanding Debt Securities of any series may on behalf of the Holders of all the Debt Securities of such series waive any past default described in clause (i), (ii), (iii), (iv) or (vi) above (or, in the case of a default described in clause (v) above, the Holders

of not less than a majority in principal amount of all Outstanding Debt Securities may waive any such past default) and its consequences, except a default (a) in the payment of the principal of (or premium, if any) or any interest on any Debt Security, or (b) in respect of a covenant or provision that cannot be modified or amended without the consent of the Holder of each Outstanding Debt Security of such series affected thereby. (Section 514)

      The trust indenture will provide that, so long as any Debt Securities are Outstanding, we will not:

      without at the same time or as soon as reasonably practicable thereafter according to the Holders of Debt Securities a ratable and pari passu interest in the same Security Interest or Guarantee, as applicable, but this covenant will not apply to, or operate to prevent:

      Modification and amendment of the trust indenture may be made by our company and the Trustee with the consent of the Holders of not less than a majority in principal amount of all Outstanding Debt Securities that are affected by such modification or amendment; provided that no such modification or amendment may, without the consent of the Holder of each Outstanding Debt Security affected thereby, among other things;

      The Holders of a majority in principal amount of Outstanding Debt Securities affected thereby have the right to waive compliance by our company with certain covenants. (Section 1008)

      Our company and the Trustee may modify and amend the trust indenture without the consent of any Holder, for any of the following purposes:

      The trust indenture provides that in determining whether the Holders of the requisite principal amount of Debt Securities of a series then Outstanding have given any request, demand, authorization, direction, notice, consent or waiver thereunder:

      The trust indenture provides that our company may not amalgamate or consolidate with or merge into any other person or convey, transfer, sell or lease our properties and assets substantially as an entirety to any Person, unless:

      In addition, no such amalgamation, consolidation, merger or transfer may be made if, as a result thereof, any property or assets of our company would become subject to any mortgage or other encumbrance securing Debt, unless such mortgage or other encumbrance could be created pursuant to the provisions described under “— Negative Pledge” above without equally and ratably securing the Debt Securities or unless the Debt Securities are secured equally and ratably with, or prior to, the Debt secured by such mortgage or other encumbrance. (Section 803)

      We may discharge certain obligations to Holders of any series of Debt Securities issued under the trust indenture which have not already been delivered to the Trustee for cancellation and which have either become due and payable or are by their terms due and payable within one year (or scheduled for redemption within one year) by irrevocably depositing with the Trustee trust funds in an amount sufficient to pay the entire indebtedness on such Debt Securities for principal (and premium, if any) and interest to the date of such deposit (if such Debt Securities have become due and payable) or to the Stated Maturity or Redemption Date, as the case may be. (Section 401)

      We may, at our option and at any time, elect to have our obligations discharged with respect to the Outstanding Debt Securities of or within any series, which we refer to as defeasance. Defeasance means that we shall be deemed to have paid and discharged the entire indebtedness represented by such Outstanding Debt Securities and to have satisfied our other obligations under the trust indenture with respect to such Debt Securities, except for:

      We may, at our option and at any time, elect to be released from our obligations with respect to certain covenants that are described in the trust indenture (including those described under “— Negative Pledge” and

“— Merger, Consolidation or Amalgamation” above), and we refer to this as “covenant defeasance,” and any omission to comply with such obligations thereafter shall not constitute a default or an Event of Default with respect to such Debt Securities. (Sections 1401, 1402 and 1403)

      In order to exercise either defeasance or covenant defeasance:

      If, after we have deposited funds and/or Government Obligations to effect defeasance or covenant defeasance with respect to any Debt Securities:

      All payments of principal of (and premium, if any), and interest, if any, on any Debt Security that is payable in a Currency other than U.S. dollars that ceases to be used by its government of issuance shall be made in U.S. dollars. (Section 312)

      Unless otherwise specified in Section 301 of the trust indenture, principal (premium, if any) and interest, if any, on Debt Securities will be payable at an office or agency maintained by our company in New York, New York, except that at our option, interest, if any, may be paid by:

      Payment of any installment of interest on Debt Securities will be made to the Person in whose name such Debt Security is registered at the close of business on the Regular Record Date for such interest. (Section 307)

      Any Paying Agent outside the United States and any other Paying Agent in the United States initially designated by our company for the Debt Securities may be established for each series of Debt Securities. We may at any time designate additional Paying Agents or rescind the designation of any Paying Agent or approve a change in the office through which any Paying Agent acts, except that we will be required to maintain a Paying Agent in each Place of Payment for such series. (Section 1002)

      The Trustee may resign or be removed with respect to one or more series of Debt Securities and a successor Trustee may be appointed to act with respect to such series. (Section 608) In the event that two or more persons are acting as Trustee with respect to different series of Debt Securities, each such Trustee shall be a Trustee of a trust under the trust indenture separate and apart from the trust administered by any other such Trustee (Section 609), and any action described herein to be taken by the “Trustee” may then be taken by each such Trustee with respect to, and only with respect to, the one or more series of Debt Securities for which it is Trustee.

      The Debt Securities of a series may be issued in whole or in part in the form of one or more Global Securities that will be deposited with, or on behalf of, a depositary for a series of Debt Securities. Global Securities may be issued in either temporary or permanent form. Unless otherwise provided for a series of Debt Securities, Debt Securities that are represented by a Global Security will be issued in denominations of US$1,000 and any integral multiple thereof or in such other denominations as may be provided for by the terms of the Debt Securities of any particular series, and will be issued in registered form only, without coupons. Payments of principal of (premium, if any) and interest on Debt Securities represented by a Global Security will be made by the Trustee to the depositary or its nominee.

      The trust indenture and the Debt Securities will be governed by, and construed in accordance with, the laws of the State of New York. The trust indenture is subject to the provisions of the Trust Indenture Legislation and shall, to the extent applicable, be governed by such provisions. (Section 111)

      The trust indenture, as currently amended and supplemented, provides that we have designated our subsidiary, Thomson Holdings Inc., Metro Center, One Station Place, Stamford, Connecticut 06902, as our authorized agent for service of process in any suit, action or proceeding arising out of or relating to the trust indenture and the Debt Securities that may be instituted in any federal or state court located in the Borough of Manhattan, in The City of New York, or brought under United States federal or state securities laws or brought by the Trustee, and have irrevocably submitted to the jurisdiction of such courts. (Section 113)

      Since some of our assets are outside the United States, any judgment obtained in the United States against us, including any judgment with respect to the payment of interest and principal on the Debt Securities, may not be collectible within the United States.

      A court of competent jurisdiction in the Province of Ontario would enforce a final and conclusive judgment in personam of a court sitting in the Borough of Manhattan, the City of New York, New York, which we refer to as a New York court, that is subsisting and unsatisfied respecting the enforcement of the trust indenture and the Debt Securities that is not impeachable as void or voidable under the internal laws of the State of New York for a sum certain if:

      We believe that a monetary judgment of a United States court predicated solely upon the civil liability provisions of United States federal securities laws would likely be enforceable in Canada if the United States court in which the judgment was obtained had a basis for jurisdiction in the matter that was recognized by a Canadian court for such purposes. We cannot assure you that this will be the case. It is less certain that an action could be brought in Canada in the first instance on the basis of liability predicated solely upon such laws.

Definitions

      Set forth below is a summary of certain of the defined terms used in the trust indenture. Reference is made to the trust indenture for the full definition of all such terms, as well as any other terms used herein for which no definition is provided. (Section 101)

      “Business Day”, when used with respect to any Place of Payment or any other location referred to in the trust indenture, expressly or impliedly, which shall include Toronto, Ontario, New York, New York and London, England, hereunder, or in the Debt Securities, means, unless otherwise specified with respect to any Debt Securities pursuant to Section 301, each Monday, Tuesday, Wednesday, Thursday and Friday which is not a day on which banking institutions in that Place of Payment or other such location are authorized or obligated by law or executive order to close.

      “Consolidated Shareholders’ Equity” means the aggregate of the stated capital accounts for all outstanding shares of our company and the amount of consolidated surplus of our company and our

Subsidiaries, whether paid in, earned, or otherwise, as such consolidated surplus is shown on the then most recent audited consolidated balance sheet of our company, determined in accordance with GAAP.

      “Debt” means notes, bonds, debentures or other similar evidences of indebtedness for money borrowed.

      “Funded Obligation” means any Debt, the principal amount of which by its terms is not payable on demand and the due date of payment of which, after giving effect to any right of extension or renewal exercisable unilaterally on the part of the obligor, is more than 18 months from the date of the creation, issue or incurring of the same.

      “GAAP” means generally accepted accounting principles which are in effect from time to time in Canada (or, if we hereafter determine to prepare our principal consolidated financial statements in accordance with generally accepted accounting principles which are in effect from time to time in the United States, such principles).

      “Guarantee” means any guarantee, indemnity or similar obligation.

      “Material Subsidiary” means any Subsidiary of our company the sales of which for the 12 months ending at the end of the most recently completed fiscal year of such Subsidiary represent 5% or more of the sales of our company and its consolidated Subsidiaries taken as a whole for the 12 months ending at the end of the most recently completed fiscal year of our company, or the gross assets of which as at the end of the most recently completed fiscal year of such Subsidiary represent 5% or more of the gross assets of our company and its consolidated Subsidiaries taken as a whole as at the end of the most recently completed fiscal year of our company, calculated in each case in accordance with GAAP.

      “Subsidiary” means any corporation of which at the time of determination our company, directly and/or indirectly through one or more Subsidiaries, owns more than 50% of the shares of Voting Stock of such corporation.

      “Trust Indenture Act” or “TIA” means the Trust Indenture Act of 1939, as amended as in force at the date as of which a trust indenture was executed, except as provided in Section 905 of the trust indenture.

      “Trust Indenture Legislation” means, at any time, statutory provisions relating to trust indentures and the rights, duties, and obligations of trustees under the trust indentures and of corporations issuing debt obligations under trust indentures to the extent that such provisions are at such time in force and applicable to the trust indenture, and at the date of a trust indenture means (i) in respect of Debt Securities offered solely in Canada and not concurrently in the United States, the applicable provisions of the Business Corporations Act (Ontario) and the regulations thereunder as amended or re-enacted from time to time, and (ii) in respect of Debt Securities offered solely in the United States and not concurrently in Canada or offered concurrently in the United States and Canada, the Trust Indenture Act and regulations thereunder.

      “Voting Stock” means stock of the class or classes having general voting power under ordinary circumstances to elect at least a majority of the board of directors, managers or trustees of a corporation (irrespective of whether or not at the time stock of any other class or classes shall have or might have voting power by reason of the happening of any contingency). (Section 101)

PLAN OF DISTRIBUTION

      We may sell the Debt Securities:

      We may sell Debt Securities at fixed prices or at non-fixed prices, such as prices determined by reference to the prevailing price of the specified securities in a specified market, at market prices prevailing at the time of sale or at prices to be negotiated with purchasers, which prices may vary as between purchasers and during

the period of distribution of the securities. The applicable prospectus supplement will set forth the terms of the offering of the Debt Securities, including the name or names of any underwriters, the purchase price of such Debt Securities and the proceeds to our company from such sale, any underwriting discounts and other items constituting underwriters’ compensation, any public offering price and any discounts or concessions allowed or reallowed or paid to dealers. Only underwriters so named in the prospectus supplement are deemed to be underwriters in connection with the Debt Securities offered thereby.

      If underwriters are used in the sale, the Debt Securities may be acquired by the underwriters for their own account and may be resold from time to time in one or more transactions, including negotiated transactions, at a fixed public offering price or at varying prices determined at the time of sale. The obligations of the underwriters to purchase such Debt Securities will be subject to certain conditions precedent, and the underwriters will be obligated to purchase all the Debt Securities of the series offered through the applicable prospectus supplement if any of such Debt Securities are purchased. Any public offering price and any discounts or concessions allowed or reallowed or paid to dealers may be changed from time to time.

      We may also sell Debt Securities directly at such prices and upon such terms as agreed to by our company and the purchaser or through agents designated by our company from time to time. Any agent involved in the offering and sale of the Debt Securities in respect of which this prospectus is delivered will be named, and any commissions payable by our company to such agent will be set forth, in the prospectus supplement. Unless otherwise indicated in the prospectus supplement, any agent is acting on a best efforts basis for the period of its appointment.

      We may agree to pay the underwriters a commission for various services relating to the issue and sale of the Debt Securities offered hereby.

      In connection with any offering of the Debt Securities, the underwriters or agents may over-allot or effect transactions which stabilize or maintain the market price of the Debt Securities offered at a level above that which might otherwise prevail in the open market. These transactions, if commenced, may be discontinued at any time. Underwriters, dealers and agents who participate in the distribution of the Debt Securities may be entitled under agreements to be entered into with our company to indemnification by our company against certain liabilities, including liabilities under securities legislation, or to contribution with respect to payments which such underwriters, dealers or agents may be required to make in respect thereof. These underwriters, dealers and agents may be customers of, engage in transactions with or perform services for our company in the ordinary course of business.

      Each series of the Debt Securities will be a new issue of securities with no established trading market. Unless otherwise specified in an applicable prospectus supplement relating to a series of Debt Securities, the Debt Securities will not be listed on any securities exchange or on any automated dealer quotation system. Some broker-dealers may make a market in the Debt Securities, but they will not be obligated to do so and may discontinue any market-making activities at any time without notice. There may not be a trading market for the Debt Securities. See “Risk Factors.”

CERTAIN INCOME TAX CONSIDERATIONS

      The applicable prospectus supplement will describe the material Canadian federal income tax consequences to an investor who is not a resident of Canada (for purposes of the Income Tax Act (Canada)) of acquiring Debt Securities, including whether payment of principal, premium, if any, and interest will be subject to Canadian non-resident withholding tax.

      A prospectus supplement will also describe any material U.S. federal income tax consequences of the acquisition, ownership and disposition of Debt Securities by an initial investor who is a U.S. person (within the meaning of the U.S. Internal Revenue Code), including any such consequences relating to Debt Securities payable in a currency other than U.S. dollars, issued at an original issue discount for U.S. federal income tax purposes or containing any early redemption provisions or other special terms.

LEGAL MATTERS

      Unless otherwise specified in the prospectus supplement, certain matters relating to the Debt Securities offered by this prospectus will be passed upon on behalf of our company by Torys LLP. As of September 19, 2005, the partners and associates of Torys LLP beneficially owned, directly or indirectly, less than 1% of our outstanding common shares. Certain partners and an associate of Torys LLP are assistant secretaries of our company and certain of our affiliates.

EXPERTS

      The consolidated financial statements as at December 31, 2004 and December 31, 2003 and for each of the years in the two-year period ended December 31, 2004 incorporated by reference in this prospectus have been so included in reliance on the report of PricewaterhouseCoopers LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

DOCUMENTS FILED AS PART OF THE REGISTRATION STATEMENT

      The following documents have been filed with the SEC as part of the registration statement on Form F-9 of which this prospectus is a part:

PART II

INFORMATION NOT REQUIRED TO BE DELIVERED TO OFFEREES OR PURCHASERS

Indemnification of Directors and Officers

      Under the Business Corporations Act (Ontario), The Thomson Corporation (the “Company”) may indemnify a present or former director or officer or a person who acts or acted at the Company’s request as a director or officer of another corporation of which the Company is or was a shareholder or creditor, and his or her heirs and legal representatives, against all costs, charges and expenses, including an amount paid to settle an action or satisfy a judgment, reasonably incurred by him or her in respect of any civil, criminal or administrative action or proceeding to which he or she is made a party by reason of being or having been a director or officer of the Company or such other corporation and provided that the director or officer acted honestly and in good faith with a view to the best interests of the Company, and, in the case of a criminal or administrative action or proceeding that is enforced by a monetary penalty, such director or officer had reasonable grounds for believing that his or her conduct was lawful. Such indemnification may be made in connection with an action by or on behalf of the Company or such other corporation to procure a judgment in its favor only with court approval. A director or officer is entitled to indemnification from the Company as a matter of right if he or she was substantially successful on the merits in his or her defense of the action or proceeding and fulfilled the conditions set forth above.

      The by-laws of the Company provide that the Company shall indemnify a director or officer, a former director or officer or a person who acts or acted at the Company’s request as a director or officer of a body corporate of which the Company is or was a shareholder or creditor, and the heirs and legal representatives of such a person against all costs, charges, expenses and liabilities incurred while carrying out such acts, except as prohibited by law.

      The by-laws of the Company further provide that the Company may, to the extent permitted by the Business Corporations Act (Ontario), purchase and maintain insurance for the benefit of any director or officer, a former director or officer or a person who acts or acted at the Company’s request as a director or officer of a body corporate of which the Company is or was a shareholder or creditor.

      A contractual indemnity is provided by The Woodbridge Company Limited, the Company’s principal shareholder, which indemnifies, subject to certain exclusions, directors and officers for losses as a result of claims against the directors and officers of the Company in their capacity as directors and officers and also reimburses the Company for payments made pursuant to the indemnity provided by the Company pursuant to the Business Corporations Act (Ontario) and the by-laws of the Company.

      In addition, the Company has entered into agreements with each of its directors which indemnify them to the maximum extent permitted by law.

      Insofar as indemnification for liabilities under the Securities Act may be permitted to directors, officers or persons controlling the Company pursuant to the foregoing provisions, the Company has been advised that in the opinion of the Commission such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable.

EXHIBITS

      References in this exhibit index to “Thomson” are to The Thomson Corporation.

PART III

UNDERTAKING AND CONSENT TO SERVICE OF PROCESS

      The Registrant undertakes to make available, in person or by telephone, representatives to respond to inquiries made by the Commission staff, and to furnish promptly, when requested to do so by the Commission staff, information related to the securities registered pursuant to this Form F-9 or to transactions in said securities.

      (a) The Registrant has previously filed with the Commission a written irrevocable consent and power of attorney on Form F-X.

      (b) Computershare Trust Company of Canada, a Trustee under the Indenture, has previously filed with the Commission a written irrevocable consent and power of attorney on Form F-X.

      (c) Any change to the name or address of the agent for service of the Registrant or Computershare Trust Company of Canada, as a Trustee, shall be communicated promptly to the Commission by amendment to Form F-X referencing the file number of this Registration Statement.

SIGNATURES

      Pursuant to the requirements of the Securities Act of 1933, as amended, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form F-9 and has duly caused this amendment to its Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Stamford, State of Connecticut, on this 20th day of September 2005.

POWER OF ATTORNEY

      Pursuant to the requirements of the Securities Act of 1933, as amended, this amendment to the Registration Statement has been signed below by the following persons in the capacities indicated on September 20, 2005.

AUTHORIZED REPRESENTATIVE

      Pursuant to the requirements of Section 6(a) of the Securities Act of 1933, the undersigned has signed this amendment to the Registration Statement, solely in the capacity of the duly authorized representative in the United States of The Thomson Corporation, in the City of Stamford, State of Connecticut, on this 20th day of September 2005.

EXHIBIT INDEX

      References in this exhibit index to “Thomson” are to The Thomson Corporation.