Blocklisting Interim Review

Spirent Communications PLC
30 July 2007

BLOCKLISTING SIX MONTHLY RETURN

To:       The FSA

Date: 30 July 2007



Name of applicant:                SPIRENT COMMUNICATIONS PLC

Name of scheme:                   SPIRENT EXECUTIVE SHARE OPTION SCHEME, 1995

Period of return:                 From: 1 JANUARY 2007            To: 30 JUNE 2007

Balance under scheme from previous return:            1,953,060 ORDINARY SHARES OF 3 1/3p EACH

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


Number of securities issued/allotted under scheme     2,755,460  ORDINARY SHARES OF 3 1/3p EACH
during period:

Balance under scheme not yet issued/allotted at end   2,197,600 ORDINARY SHARES OF 3 1/3p EACH
of period:

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

                                                      3,000,000 ORDINARY SHARES OF 3 1/3p EACH DATED 9
                                                      MARCH 2007

Total number of securities in issue at the end of the 963,752,473 ORDINARY SHARES OF 3 1/3 p EACH
period :                                              (887,007,473 WHEN EXCLUDING TREASURY SHARES)


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 BY        Warren Nash
                 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: 30 July 2007




Name of applicant:                SPIRENT COMMUNICATIONS PLC

Name of scheme:                   U.S. EMPLOYEE STOCK PURCHASE PLAN

Period of return:                 From: 1 JANUARY 2007            To: 30 JUNE 2007

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

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


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

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

Number and class of securities originally listed and  435,000 ORDINARY SHARES OF 3 1/3p EACH DATED 5 JUNE
the date of admission:                                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 the end of the 963,752,473 ORDINARY SHARES OF 3 1/3 p EACH
period :                                              (887,007,473 WHEN EXCLUDING TREASURY SHARES)


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 BY        Warren Nash
                 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: 30 July 2007




Name of applicant:                SPIRENT COMMUNICATIONS PLC

Name of scheme:                   SPIRENT GLOBAL ALL EMPLOYEE SHARE PURCHASE PLAN

Period of return:                 From: 1 JANUARY 2007            To: 30 JUNE 2007

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

The amount by which the block scheme has been         NIL
increased, if the scheme has been increased since the

date of the last return:


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

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

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

                                                      700,000 ORDINARY SHARES OF 3 1/3 p EACH DATED 6
                                                      DECEMBER 2004

Total number of securities in issue at the end of the 963,752,473 ORDINARY SHARES OF 3 1/3 p EACH
period :                                              (887,007,473 WHEN EXCLUDING TREASURY SHARES)


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 BY        Warren Nash
                 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: 30 July 2007




Name of applicant:                SPIRENT COMMUNICATIONS PLC

Name of scheme:                   NETCOM AMENDED AND RESTATED STOCK OPTION PLAN

Period of return:                 From: 1 JANUARY 2007            To: 30 JUNE 2007

Balance under scheme from previous return:            3,060,733 ORDINARY SHARES OF 3 1/3p EACH

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


Number of securities issued/allotted under scheme     659,275 ORDINARY SHARES OF 3 1/3p EACH
during period:

Balance under scheme not yet issued/allotted at end   2,401,458 ORDINARY SHARES OF 3 1/3p EACH
of period:

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

                                                      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

                                                      2,500,000 ORDINARY SHARES OF 3 1/3 p EACH DATED 19
                                                      OCTOBER 2006
Total number of securities in issue at the end of the 963,752,473 ORDINARY SHARES OF 3 1/3 p EACH
period :                                              (887,007,473 WHEN EXCLUDING TREASURY SHARES)


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 BY        Warren Nash
                 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: 30 July 2007




Name of applicant:                SPIRENT COMMUNICATIONS PLC

Name of scheme:                   ZARAK AMENDED AND RESTATED STOCK OPTION PLAN

Period of return:                 From: 1 JANUARY 2007            To: 30 JUNE 2007

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

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


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

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

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

Total number of securities in issue at the end of the 963,752,473 ORDINARY SHARES OF 3 1/3 p EACH
period :                                              (887,007,473 WHEN EXCLUDING TREASURY SHARES)


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 BY        Warren Nash
                 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: 30 July 2007




Name of applicant:                SPIRENT COMMUNICATIONS PLC

Name of scheme:                   SPIRENT SAVINGS RELATED SHARE OPTION SCHEME

Period of return:                 From: 1 JANUARY 2007            To: 30 JUNE 2007

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

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


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

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

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

Total number of securities in issue at the end of the 963,752,473 ORDINARY SHARES OF 3 1/3 p EACH
period :                                              (887,007,473 WHEN EXCLUDING TREASURY SHARES)


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 BY        Warren Nash
                 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: 30 July 2007




Name of applicant:                SPIRENT COMMUNICATIONS PLC

Name of scheme:                   SPIRENT STOCK INCENTIVE PLAN

Period of return:                 From: 1 JANUARY 2007            To: 30 JUNE 2007

Balance under scheme from previous return:            1,946,196 ORDINARY SHARES OF 3 1/3p EACH

The amount by which the block scheme has been         5,100,000 ORDINARY SHARES OF 3 1/3p EACH
increased, if the scheme has been increased since the
date of the last return:


Number of securities issued/allotted under scheme     4,607,719 ORDINARY SHARES OF 3 1/3p EACH
during period:

Balance under scheme not yet issued/allotted at end   2,438,477 ORDINARY SHARES OF 3 1/3p EACH
of period:

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

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

                                                      4,000,000 ORDINARY SHARES OF 3 1/3 p EACH DATED 17
                                                      JUNE 2005

                                                      2,800,000 ORDINARY SHARES OF 3 1/3 p EACH DATED 16
                                                      FEBRUARY 2007

                                                      2,300,000 ORDINARY SHARES OF 3 1/3 p EACH DATED 13
                                                      JULY 2007
Total number of securities in issue at the end of the 963,752,473 ORDINARY SHARES OF 3 1/3 p EACH
period :                                              (887,007,473 WHEN EXCLUDING TREASURY SHARES)


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 BY        Warren Nash
                 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: 30 July 2007




Name of applicant:                SPIRENT COMMUNICATIONS PLC

Name of scheme:                   CAW AMENDED AND RESTATED STOCK OPTION PLAN

Period of return:                 From: 1 JANUARY 2007            To: 30 JUNE 2007

Balance under scheme from previous return:            815,120 ORDINARY SHARES OF 3 1/3p EACH

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


Number of securities issued/allotted under scheme     37,454  ORDINARY SHARES OF 3 1/3p EACH
during period:

Balance under scheme not yet issued/allotted at end   777,666 ORDINARY SHARES OF 3 1/3p EACH
of period:

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

                                                      115,394 ORDINARY SHARES OF 3 1/3 p EACH DATED 28
                                                      AUGUST 2002
Total number of securities in issue at the end of the 963,752,473 ORDINARY SHARES OF 3 1/3 p EACH
period :                                              (887,007,473 WHEN EXCLUDING TREASURY SHARES)


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 BY        Warren Nash
                 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: 30 July 2007




Name of applicant:                SPIRENT COMMUNICATIONS PLC

Name of scheme:                   SPIRENT EMPLOYEE INCENTIVE PLAN 2005

Period of return:                 From: 1 JANUARY 2007            To: 30 JUNE 2007

Balance under scheme from previous return:            NIL

The amount by which the block scheme has been         3,300,000 ORDINARY SHARES OF 3 1/3p EACH
increased, if the scheme has been increased since the
date of the last return:


Number of securities issued/allotted under scheme     92,566 ORDINARY SHARES OF 3 1/3p EACH
during period:

Balance under scheme not yet issued/allotted at end   3,207,434 ORDINARY SHARES OF 3 1/3p EACH
of period:

Number and class of securities originally listed and  3,300,000 ORDINARY SHARES OF 3 1/3p EACH DATED 19
the date of admission:                                JANUARY 2007

Total number of securities in issue at the end of the 963,752,473 ORDINARY SHARES OF 3 1/3 p EACH
period :                                              (887,007,473 WHEN EXCLUDING TREASURY SHARES)


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 BY        Warren Nash
                 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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