Blocklisting Interim Review

Spirent Communications PLC
07 January 2008

BLOCKLISTING SIX MONTHLY RETURN



To:       The FSA



Date: 7 January 2008




Name of applicant:                SPIRENT COMMUNICATIONS PLC

Name of scheme:                   SPIRENT EXECUTIVE SHARE OPTION SCHEME, 1995

Period of return:                 From: 1 JULY 2007               To: 31 DECEMBER 2007

Balance under scheme from previous return:            2,197,600 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     50,000 ORDINARY SHARES OF 3 1/3p EACH
during period:

Balance under scheme not yet issued/allotted at end   2,147,600 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 840,776,679 ORDINARY SHARES OF 3 1/3 p EACH
period :                                              (792,361,076 WHEN EXCLUDING TREASURY SHARES)


Name of contact:                                        Warren Nash

Address of contact:                                     Spirent Communications plc
                                                        Northwood Park
                                                        Gatwick Road
                                                        Crawley
                                                        West Sussex
                                                        RH10 9XN

Telephone number of contact:                            01293 767657


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: 7 January 2008




Name of applicant:                SPIRENT COMMUNICATIONS PLC

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

Period of return:                 From: 1 JULY 2007               To: 31 DECEMBER 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 840,776,679 ORDINARY SHARES OF 3 1/3 p EACH
period :                                              (792,361,076 WHEN EXCLUDING TREASURY SHARES)


Name of contact:                                        Warren Nash

Address of contact:                                     Spirent Communications plc
                                                        Northwood Park
                                                        Gatwick Road
                                                        Crawley
                                                        West Sussex
                                                        RH10 9XN

Telephone number of contact:                            01293 767657


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: 7 January 2008




Name of applicant:                SPIRENT COMMUNICATIONS PLC

Name of scheme:                   SPIRENT GLOBAL ALL EMPLOYEE SHARE PURCHASE PLAN

Period of return:                 From: 1 JULY 2007               To: 31 DECEMBER 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 840,776,679 ORDINARY SHARES OF 3 1/3 p EACH
period :                                              (792,361,076 WHEN EXCLUDING TREASURY SHARES)


Name of contact:                                        Warren Nash

Address of contact:                                     Spirent Communications plc
                                                        Northwood Park
                                                        Gatwick Road
                                                        Crawley
                                                        West Sussex
                                                        RH10 9XN

Telephone number of contact:                            01293 767657


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: 7 January 2008




Name of applicant:                SPIRENT COMMUNICATIONS PLC

Name of scheme:                   NETCOM AMENDED AND RESTATED STOCK OPTION PLAN

Period of return:                 From: 1 JULY 2007               To: 31 DECEMBER 2007

Balance under scheme from previous return:            2,467,603 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     897,549 ORDINARY SHARES OF 3 1/3p EACH
during period:

Balance under scheme not yet issued/allotted at end   1,570,054 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 840,776,679 ORDINARY SHARES OF 3 1/3 p EACH
period :                                              (792,361,076 WHEN EXCLUDING TREASURY SHARES)


Name of contact:                                        Warren Nash

Address of contact:                                     Spirent Communications plc
                                                        Northwood Park
                                                        Gatwick Road
                                                        Crawley
                                                        West Sussex
                                                        RH10 9XN

Telephone number of contact:                            01293 767657


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: 7 January 2008




Name of applicant:                SPIRENT COMMUNICATIONS PLC

Name of scheme:                   ZARAK AMENDED AND RESTATED STOCK OPTION PLAN

Period of return:                 From: 1 JULY 2007               To: 31 DECEMBER 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 840,776,679 ORDINARY SHARES OF 3 1/3 p EACH
period :                                              (792,361,076 WHEN EXCLUDING TREASURY SHARES)


Name of contact:                                        Warren Nash

Address of contact:                                     Spirent Communications plc
                                                        Northwood Park
                                                        Gatwick Road
                                                        Crawley                   
                                                        West Sussex
                                                        RH10 9XN

Telephone number of contact:                            01293 767657


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: 7 January 2008




Name of applicant:                SPIRENT COMMUNICATIONS PLC

Name of scheme:                   SPIRENT SAVINGS RELATED SHARE OPTION SCHEME

Period of return:                 From: 1 JULY 2007               To: 31 DECEMBER 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 840,776,679 ORDINARY SHARES OF 3 1/3 p EACH
period :                                              (792,361,076 WHEN EXCLUDING TREASURY SHARES)


Name of contact:                                        Warren Nash

Address of contact:                                     Spirent Communications plc
                                                        Northwood Park
                                                        Gatwick Road
                                                        Crawley
                                                        West Sussex
                                                        RH10 9XN

Telephone number of contact:                            01293 767657


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: 7 January 2008




Name of applicant:                SPIRENT COMMUNICATIONS PLC

Name of scheme:                   SPIRENT STOCK INCENTIVE PLAN

Period of return:                 From: 1 JULY 2007               To: 31 DECEMBER 2007

Balance under scheme from previous return:            1,150,651 ORDINARY SHARES OF 3 1/3p EACH

The amount by which the block scheme has been         2,300,000 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     2,134,701 ORDINARY SHARES OF 3 1/3p EACH
during period:

Balance under scheme not yet issued/allotted at end   1,315,950 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 840,776,679 ORDINARY SHARES OF 3 1/3 p EACH
period :                                              (792,361,076 WHEN EXCLUDING TREASURY SHARES)


Name of contact:                                        Warren Nash

Address of contact:                                     Spirent Communications plc
                                                        Northwood Park
                                                        Gatwick Road
                                                        Crawley
                                                        West Sussex
                                                        RH10 9XN

Telephone number of contact:                            01293 767657


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: 7 January 2008




Name of applicant:                SPIRENT COMMUNICATIONS PLC

Name of scheme:                   CAW AMENDED AND RESTATED STOCK OPTION PLAN

Period of return:                 From: 1 JULY 2007               To: 31 DECEMBER 2007

Balance under scheme from previous return:            777,666 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   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 840,776,679 ORDINARY SHARES OF 3 1/3 p EACH
period :                                              (792,361,076 WHEN EXCLUDING TREASURY SHARES)


Name of contact:                                        Warren Nash

Address of contact:                                     Spirent Communications plc
                                                        Northwood Park
                                                        Gatwick Road
                                                        Crawley
                                                        West Sussex
                                                        RH10 9XN

Telephone number of contact:                            01293 767657


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: 7 January 2008




Name of applicant:                SPIRENT COMMUNICATIONS PLC

Name of scheme:                   SPIRENT EMPLOYEE INCENTIVE PLAN 2005

Period of return:                 From: 1 JULY 2007               To: 31 DECEMBER 2007

Balance under scheme from previous return:            3,215,264 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     28,105 ORDINARY SHARES OF 3 1/3p EACH
during period:

Balance under scheme not yet issued/allotted at end   3,187,159 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 840,776,679 ORDINARY SHARES OF 3 1/3 p EACH
period :                                              (792,361,076 WHEN EXCLUDING TREASURY SHARES)


Name of contact:                                        Warren Nash

Address of contact:                                     Spirent Communications plc
                                                        Northwood Park
                                                        Gatwick Road
                                                        Crawley
                                                        West Sussex
                                                        RH10 9XN

Telephone number of contact:                            01293 767657


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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