SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    FORM 6-K

                        REPORT OF FOREIGN PRIVATE ISSUER
                      Pursuant to Rule 13a-16 or 15d-16 Under
                       the Securities Exchange Act of 1934

                         For the month of March, 2005
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                        Commission File Number 001-13908
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                                  AMVESCAP PLC
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                 (Translation of registrant's name into English)

                 30 Finsbury Square, London EC2A 1AG, ENGLAND
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                    (Address of principal executive offices)


Indicate by check mark whether the registrant files or will file annual reports
under cover Form 20-F or Form 40-F.

                        Form 20-F  X             Form 40-F
                                 -----                    -----

Indicate by check mark if the registrant is submitting the Form 6-K in paper as
permitted by Regulation S-T Rule 101(b)(1): 
                                           ------

Indicate by check mark if the registrant is submitting the Form 6-K in paper as
permitted by Regulation S-T Rule 101(b)(7):
                                           ------

Indicate by check mark whether by furnishing the information contained in this
Form, the registrant is also thereby furnishing the information to the
Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934.

                        Yes        No   X
                           -------   -------   

If "Yes" is marked, indicate below the file number assigned to the registrant in
connection with Rule 12g3-2(b): 82-     N/A
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Description of document filed:  BLOCKLISTING SIX-MONTHLY RETURN
                                -------------------------------




AMVESCAP PLC
IMMEDIATE RELEASE  15 MARCH 2005
CONTACT: ANGELA TULLY  TEL: 020 7065 3652


                                   SCHEDULE 5

                         BLOCKLISTING SIX-MONTHLY RETURN

To:        Listing Applications
           UK Listing Authority
           Financial Services Authority
           25, The North Colonnade
           Canary Wharf
           London, E14 5HS

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Please ensure the entries on this return are typed
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1. Name of company:         AMVESCAP PLC
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2. Name of scheme:          AIM MANAGEMENT GROUP SHARE OPTION SCHEMES
                            (FILE REF.A/3693/1997)
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3. Period of return:          FROM: 4 SEPTEMBER 2004 TO 3 MARCH 2005
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4. Number and class of        948,553 ORDINARY SHARES OF 25P EACH 
   shares (amount of 
   stock/debt security) 
   not issued under scheme
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5. Number of shares           0 ORDINARY SHARES OF 25P EACH 
   issued/allotted under
   scheme during period
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6. Balance under scheme       948,553 ORDINARY SHARES OF 25P EACH
   not yet issued/allotted
   at end of period
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7. Number and class of        37,000,000 ORDINARY SHARES OF 25P EACH 
   share(s) (amount of        LISTED ON 3 SEPTEMBER 1997
   stock/debt securities)
   originally listed and
   the date of admission
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Please confirm total number   810,805,635 ORDINARY SHARES OF 25P EACH
of shares in issue at the
end of the period in order
for us to update our records
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Contact for queries:          ANGELA TULLY
                              TELEPHONE: 020 7065 3652
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Person making return          ANGELA TULLY - ASSISTANT COMPANY SECRETARY
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                                   SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned, thereunto duly authorized.



                                                AMVESCAP PLC
                                        ------------------------------
                                                (Registrant)



Date  15 March, 2005                   By   /s/  Angela Tully
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                                                (Signature)

                                            Angela Tully
                                            Assistant Company Secretary