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                                                                    Exhibit 4.54

                             SUPPLEMENTAL INDENTURE

         SUPPLEMENTAL INDENTURE, dated as of August 6, 2002, among CANWEST MEDIA
INC., a corporation incorporated under the federal laws of Canada (the
"Issuer"), each of the New Guarantors (as defined herein); and The Bank of New
York, as trustee (the "Trustee").

         WHEREAS, in accordance with Section 11.04 of the Indenture relating to
the 10-5/8% Senior Subordinated Notes due 2011 of the Issuer, dated as of May
17, 2001 (the "Indenture"), between the Company, the Trustee and the Guarantors
(as defined therein), each of the entities listed on Exhibit A hereto (each a
"New Guarantor") desires to guarantee the obligations of the Issuer with respect
to the Notes on the terms set forth in the Indenture;

         WHEREAS, the Boards of Directors of the Issuer and each of the New
Guarantors have authorized this Supplemental Indenture; and

         WHEREAS, all things necessary to make this Supplemental Indenture a
valid supplement to the Indenture according to its terms and the terms of the
Indenture have been done:

         NOW, THEREFORE, each party agrees as follows for the benefit of the
other parties and for the equal and ratable benefit of Holders of the Notes:

         Section 1.        Guarantee. Each New Guarantor covenants and agrees
to be bound by and subject to the terms of the Indenture as if they had executed
the same as a Guarantor as of the date first set forth above.

         Section 2.        Certain Defined Terms. All capitalized terms used and
not otherwise defined herein shall have the meanings ascribed to them in the
Indenture.

         Section 3.        Governing Law. THIS SUPPLEMENTAL INDENTURE SHALL BE
GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK,
WITHOUT REGARD TO PRINCIPLES OF CONFLICTS OF LAW. EACH OF THE PARTIES HERETO
AGREES TO SUBMIT TO THE JURISDICTION OF THE COURTS OF THE STATE OF NEW YORK IN
ANY ACTION OR PROCEEDING ARISING OUT OF OR RELATING TO THIS SUPPLEMENTAL
INDENTURE, THE NOTES OR THE GUARANTEES.

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         Section 4.        Multiple Counterparts. The parties may sign multiple
counterparts of this Supplemental Indenture. Each signed counterpart shall be
deemed an original, but all of them together represent one and the same
agreement.

         IN WITNESS WHEREOF, the parties have caused this Supplemental Indenture
to be duly executed all as of the date and year first written above.

                      CANWEST MEDIA INC.

                      By: /s/ John Maguire
                          ----------------
                          Name:  John Maguire
                          Title: Vice President, Finance
                                 and Chief Financial Officer

                      3919056 Canada Limited
                      Fox Sports World Canada Holdco Inc.
                      Global Television Specialty Networks Inc.
                      Lonestar Holdco Inc.
                      Radio Otago Holdings Limited
                      ReachCanada Contact Centre Limited
                      RetroVista Holdco Inc.
                      Vancouver Island Newspaper Group Inc.
                      Xtreme Sports Holdco Inc., each as a Guarantor

                      By: /s/ John Maguire
                          ----------------
                          Name:  John Maguire
                          Title: Authorized Signing Officer

                      THE BANK OF NEW YORK,
                          not in its individual capacity, but solely as Trustee

                      By: /s/ Vanessa Mack
                          ----------------
                          Name:  Vanessa Mack
                          Title: Assistant Vice President

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                                                                       Exhibit A

New Guarantors

3919056 Canada Limited
Fox Sports World Canada Holdco Inc.
Global Television Specialty Networks Inc.
Lonestar Holdco Inc.
Radio Otago Holdings Limited
ReachCanada Contact Centre Limited
RetroVista Holdco Inc.
Vancouver Island Newspaper Group Inc.
Xtreme Sports Holdco Inc.

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