SOURCE: Spirent Communications PLC

July 28, 2006 11:34 ET

Spirent Communications PLC - Blocklisting Interim Review

Crawley, UK -- (MARKET WIRE) -- July 28, 2006 --

BLOCKLISTING SIX MONTHLY RETURN


To: The FSA


Date: 28 July 2006



Name of applicant:           SPIRENT COMMUNICATIONS PLC

Name of scheme:              SPIRENT EXECUTIVE SHARE OPTION SCHEME, 1995

Period of return:            From: 1 JANUARY 2006   To: 30 JUNE 2006

Balance under scheme from previous        2,386,034 ORDINARY SHARES OF 3 1/3p
return:                                   EACH

The amount by which the block scheme has  3,500,000 ORDINARY SHARES OF 3 1/3p
been increased, if the scheme has been    EACH
increased since the date of the last
return:

Number of securities issued/allotted      1,753,775 ORDINARY SHARES OF 3 1/3p
under scheme during period:               EACH

Balance under scheme not yet issued/      4,132,259 ORDINARY SHARES OF 3 1/3p
allotted at end of period:                EACH

Number and class of securities originally 3,000,000 ORDINARY SHARES OF 3 1/3p
listed and the date of admission:         EACH DATED 29 SEPTEMBER 2000

                                          3,000,000 ORDINARY SHARES OF 3 1/3 p
                                          EACH DATED 28 MAY 2004

                                          3,500,000 ORDINARY SHARES OF 3 1/3p
                                          EACH DATED 14 MARCH 2006

Total number of securities in issue at    970,810,133 ORDINARY SHARES OF 3 1/3 p
the end of the period :                   EACH


Name of contact:                           Warren Nash

Address of contact:                        Spirent Communications plc
                                           Spirent House
                                           Crawley Business Quarter
                                           Fleming Way
                                           Crawley, RH10 9QL

Telephone number of contact:               01293 767676

SIGNED  Warren Nash
BY      Director/company secretary/suitably experienced employee/duly authorised
        officer, for and on behalf of
        Spirent Communications plc
        Name of applicant



 If you knowingly or recklessly give false or misleading information you may be
                             liable to prosecution.


BLOCKLISTING SIX MONTHLY RETURN


To: The FSA


Date: 28 July 2006



Name of applicant:             SPIRENT COMMUNICATIONS PLC

Name of scheme:                U.S EMPLOYEE STOCK PURCHASE PLAN

Period of return:              From: 1 JANUARY 2006  To: 30 JUNE 2006

Balance under scheme from previous        1,237,364 ORDINARY SHARES OF 3 1/3p
return:                                   EACH

The amount by which the block scheme has  NIL
been increased, if the scheme has been
increased since the date of the last
return:

Number of securities issued/allotted      NIL
under scheme during period:

Balance under scheme not yet issued/      1,237,364 ORDINARY SHARES OF 3 1/3p
allotted at end of period:                EACH

Number and class of securities originally 435,000 ORDINARY SHARES OF 3 1/3p EACH
listed and the date of admission:         DATED 5 JUNE 2001

                                          3,500,000 ORDINARY SHARES OF 3 1/3 p
                                          EACH DATED 1 NOVEMBER 2001

                                          7,000,000 ORDINARY SHARES OF 3 1/3 p
                                          EACH DATED 18 NOVEMBER 2002

                                          1,800,000 ORDINARY SHARES OF 3 1/3 p
                                          EACH DATED 6 DECEMBER 2004

Total number of securities in issue at    970,810,133 ORDINARY SHARES OF 3 1/3 p
the end of the period :                   EACH


Name of contact:                           Warren Nash

Address of contact:                        Spirent Communications plc
                                           Spirent House
                                           Crawley Business Quarter
                                           Fleming Way
                                           Crawley, RH10 9QL

Telephone number of contact:               01293 767676

SIGNED  Warren Nash
BY      Director/company secretary/suitably experienced employee/duly authorised
        officer, for and on behalf of
        Spirent Communications plc
        Name of applicant


 If you knowingly or recklessly give false or misleading information you may be
                             liable to prosecution.


BLOCKLISTING SIX MONTHLY RETURN


To: The FSA


Date: 28 July 2006



Name of applicant:          SPIRENT COMMUNICATIONS PLC

Name of scheme:             SPIRENT GLOBAL ALL EMPLOYEE SHARE PURCHASE PLAN

Period of return:           From: 1 JANUARY 2006   To: 30 JUNE 2006

Balance under scheme from previous       814,444 ORDINARY SHARES OF 3 1/3p EACH
return:

The amount by which the block scheme has NIL
been increased, if the scheme has been
increased since the date of the last
return:

Number of securities issued/allotted     NIL
under scheme during period:

Balance under scheme not yet issued/     814,444 ORDINARY SHARES OF 3 1/3p EACH
allotted at end of period:

Number and class of securities           1,000,000 ORDINARY SHARES OF 3 1/3p
originally listed and the date of        EACH DATED 18 NOVEMBER 2002
admission:
                                         700,000 ORDINARY SHARES OF 3 1/3 p EACH
                                         DATED 6 DECEMBER 2004

Total number of securities in issue at   970,810,133 ORDINARY SHARES OF 3 1/3 p
the end of the period :                  EACH


Name of contact:                           Warren Nash

Address of contact:                        Spirent Communications plc
                                           Spirent House
                                           Crawley Business Quarter
                                           Fleming Way
                                           Crawley, RH10 9QL

Telephone number of contact:               01293 767676

SIGNED  Warren Nash
BY      Director/company secretary/suitably experienced employee/duly authorised
        officer, for and on behalf of
        Spirent Communications plc
        Name of applicant


 If you knowingly or recklessly give false or misleading information you may be
                             liable to prosecution.


BLOCKLISTING SIX MONTHLY RETURN


To: The FSA


Date: 28 July 2006



Name of applicant:          SPIRENT COMMUNICATIONS PLC

Name of scheme:             NETCOM AMENDED AND RESTATED STOCK OPTION PLAN

Period of return:           From: 1 JANUARY 2006   To: 30 JUNE 2006

Balance under scheme from previous       4,200,894 ORDINARY SHARES OF 3 1/3p
return:                                  EACH

The amount by which the block scheme has NIL
been increased, if the scheme has been
increased since the date of the last
return:

Number of securities issued/allotted     2,674,007 ORDINARY SHARES OF 3 1/3p
under scheme during period:              EACH

Balance under scheme not yet issued/     1,526,887 ORDINARY SHARES OF 3 1/3p
allotted at end of period:               EACH

Number and class of securities           3,291,399 ORDINARY SHARES OF 3 1/3p
originally listed and the date of        EACH DATED 3 SEPTEMBER 1999
admission:
                                         1,739,130 ORDINARY SHARES OF 3 1/3 p
                                         EACH DATED 8 JULY 2002

                                         6,722,689 ORDINARY SHARES OF 3 1/3 p
                                         EACH DATED 8 OCTOBER 2002

Total number of securities in issue at   970,810,133 ORDINARY SHARES OF 3 1/3 p
the end of the period :                  EACH


Name of contact:                           Warren Nash

Address of contact:                        Spirent Communications plc
                                           Spirent House
                                           Crawley Business Quarter
                                           Fleming Way
                                           Crawley, RH10 9QL

Telephone number of contact:               01293 767676

SIGNED  Warren Nash
BY      Director/company secretary/suitably experienced employee/duly authorised
        officer, for and on behalf of
        Spirent Communications plc
        Name of applicant


 If you knowingly or recklessly give false or misleading information you may be
                             liable to prosecution.


BLOCKLISTING SIX MONTHLY RETURN


To: The FSA


Date: 28 July 2006



Name of applicant:           SPIRENT COMMUNICATIONS PLC

Name of scheme:              ZARAK AMENDED AND RESTATED STOCK OPTION PLAN

Period of return:            From: 1 JANUARY 2006   To: 30 JUNE 2006

Balance under scheme from previous        2,690,996 ORDINARY SHARES OF 3 1/3p
return:                                   EACH

The amount by which the block scheme has  NIL
been increased, if the scheme has been
increased since the date of the last
return:

Number of securities issued/allotted      NIL
under scheme during period:

Balance under scheme not yet issued/      2,690,996 ORDINARY SHARES OF 3 1/3p
allotted at end of period:                EACH

Number and class of securities originally 3,895,474 ORDINARY SHARES OF 3 1/3p
listed and the date of admission:         EACH DATED 14 NOVEMBER 2000

Total number of securities in issue at    970,810,133 ORDINARY SHARES OF 3 1/3 p
the end of the period :                   EACH


Name of contact:                           Warren Nash

Address of contact:                        Spirent Communications plc
                                           Spirent House
                                           Crawley Business Quarter
                                           Fleming Way
                                           Crawley, RH10 9QL

Telephone number of contact:               01293 767676

SIGNED  Warren Nash
BY      Director/company secretary/suitably experienced employee/duly authorised
        officer, for and on behalf of
        Spirent Communications plc
        Name of applicant


I If you knowingly or recklessly give false or misleading information you may be
                             liable to prosecution.


BLOCKLISTING SIX MONTHLY RETURN


To: The FSA


Date: 28 July 2006



Name of applicant:           SPIRENT COMMUNICATIONS PLC

Name of scheme:              SPIRENT SAVINGS RELATED SHARE OPTION SCHEME

Period of return:            From: 1 JANUARY 2006   To: 30 JUNE 2006

Balance under scheme from previous        68,185 ORDINARY SHARES OF 3 1/3p EACH
return:

The amount by which the block scheme has  NIL
been increased, if the scheme has been
increased since the date of the last
return:

Number of securities issued/allotted      NIL
under scheme during period:

Balance under scheme not yet issued/      68,185 ORDINARY SHARES OF 3 1/3p EACH
allotted at end of period:

Number and class of securities originally 200,000 ORDINARY SHARES OF 3 1/3p EACH
listed and the date of admission:         DATED 31 DECEMBER 2003

Total number of securities in issue at    970,810,133 ORDINARY SHARES OF 3 1/3 p
the end of the period :                   EACH


Name of contact:                           Warren Nash

Address of contact:                        Spirent Communications plc
                                           Spirent House
                                           Crawley Business Quarter
                                           Fleming Way
                                           Crawley, RH10 9QL

Telephone number of contact:               01293 767676

SIGNED  Warren Nash
BY      Director/company secretary/suitably experienced employee/duly authorised
        officer, for and on behalf of
        Spirent Communications plc
        Name of applicant


 If you knowingly or recklessly give false or misleading information you may be
                             liable to prosecution.


BLOCKLISTING SIX MONTHLY RETURN


To: The FSA


Date: 28 July 2006



Name of applicant:              SPIRENT COMMUNICATIONS PLC

Name of scheme:                 SPIRENT STOCK INCENTIVE PLAN

Period of return:               From: 1 JANUARY 2006  To: 30 JUNE 2006

Balance under scheme from previous return: 4,453,686 ORDINARY SHARES OF 3 1/3p
                                           EACH

The amount by which the block scheme has   NIL
been increased, if the scheme has been
increased since the date of the last
return:

Number of securities issued/allotted under 589,855 ORDINARY SHARES OF 3 1/3p
scheme during period:                      EACH

Balance under scheme not yet issued/       3,863,831 ORDINARY SHARES OF 3 1/3p
allotted at end of period:                 EACH

Number and class of securities originally  3,720,930 ORDINARY SHARES OF 3 1/3p
listed and the date of admission:          EACH DATED 1 OCTOBER 2003


                                           3,703,703 ORDINARY SHARES OF 3 1/3 p
                                           EACH DATED 2 OCTOBER 2003

Total number of securities in issue at the 970,810,133 ORDINARY SHARES OF 3 1/3
end of the period :                        p EACH


Name of contact:                           Warren Nash

Address of contact:                        Spirent Communications plc
                                           Spirent House
                                           Crawley Business Quarter
                                           Fleming Way
                                           Crawley, RH10 9QL

Telephone number of contact:               01293 767676

SIGNED  Warren Nash
BY      Director/company secretary/suitably experienced employee/duly authorised
        officer, for and on behalf of
        Spirent Communications plc
        Name of applicant


 If you knowingly or recklessly give false or misleading information you may be
                             liable to prosecution.





BLOCKLISTING SIX MONTHLY RETURN


To: The FSA


Date: 28 July 2006



Name of applicant:           SPIRENT COMMUNICATIONS PLC

Name of scheme:              CAW AMENDED AND RESTATED STOCK OPTION PLAN

Period of return:            From: 1 JANUARY 2006   To: 30 JUNE 2006

Balance under scheme from previous        836,399 ORDINARY SHARES OF 3 1/3p EACH
return:

The amount by which the block scheme has  NIL
been increased, if the scheme has been
increased since the date of the last
return:

Number of securities issued/allotted      2,914 ORDINARY SHARES OF 3 1/3p EACH
under scheme during period:

Balance under scheme not yet issued/      833,485 ORDINARY SHARES OF 3 1/3p EACH
allotted at end of period:

Number and class of securities originally 1,300,000 ORDINARY SHARES OF 3 1/3p
listed and the date of admission:         EACH DATED 15 AUGUST 2002

                                          115,394 ORDINARY SHARES OF 3 1/3 p
                                          EACH DATED 28 AUGUST 2002

Total number of securities in issue at    970,810,133 ORDINARY SHARES OF 3 1/3 p
the end of the period :                   EACH


Name of contact:                           Warren Nash

Address of contact:                        Spirent Communications plc                                           Spirent House
                                           Crawley Business Quarter
                                           Fleming Way
                                           Crawley, RH10 9QL

Telephone number of contact:               01293 767676

SIGNED  Warren Nash
BY      Director/company secretary/suitably experienced employee/duly authorised
        officer, for and on behalf of
        Spirent Communications plc
        Name of applicant


If you knowingly or recklessly give false or misleading information you may be
liable to prosecution.

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