Spirent Communications plc announces Blocklisting Interim Review


Crawley, UK -- (MARKET WIRE) -- January 9, 2007 --

BLOCKLISTING SIX MONTHLY RETURN


To: The FSA


Date: 9 January 2007



Name of applicant:  SPIRENT COMMUNICATIONS PLC
Name of scheme:     SPIRENT EXECUTIVE SHARE OPTION SCHEME, 1995
Period of return:   From: 1 JULY 2006        To: 31 DECEMBER 2006
Balance under scheme from previous  4,132,259 ORDINARY SHARES OF 3 1/3p
return:                             EACH
The amount by which the block       NIL
scheme has been increased, if the
scheme has been increased since the
date of the last return:
Number of securities issued/        2,179,199 ORDINARY SHARES OF 3 1/3p
allotted under scheme during        EACH
period:
Balance under scheme not yet issued 1,953,060 ORDINARY SHARES OF 3 1/3p
/allotted at end of period:         EACH
Number and class of securities      3,000,000 ORDINARY SHARES OF 3 1/3p
originally listed and the date of   EACH DATED 29 SEPTEMBER 2000
admission:
                                    3,000,000 ORDINARY SHARES OF 3 1/3p 
                                    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 975,851,486 ORDINARY SHARES OF 
                                    3 1/3 p EACH (885,599,999 WHEN

at the end of the period :          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: 9 January 2007



Name of applicant:  SPIRENT COMMUNICATIONS PLC
Name of scheme:     U.S EMPLOYEE STOCK PURCHASE PLAN
Period of return:   From: 1 JULY 2006        To: 31 DECEMBER 2006
Balance under scheme from previous  1,237,364 ORDINARY SHARES OF 3 1/3p
return:                             EACH
The amount by which the block       NIL
scheme has been increased, if the
scheme has been increased since the
date of the last return:
Number of securities issued/        NIL
allotted 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      435,000 ORDINARY SHARES OF 3 1/3p
originally listed and the date of   EACH DATED 5 JUNE 2001
admission:
                                    3,500,000 ORDINARY SHARES OF 3 1/3p 
                                    EACH DATED 1 NOVEMBER 2001

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

                                    1,800,000 ORDINARY SHARES OF 3 1/3p 
                                    EACH DATED 6 DECEMBER 2004
Total number of securities in issue 975,851,486 ORDINARY SHARES OF 
at the end of the period :          3 1/3p EACH (885,599,999 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: 9 January 2007


Name of applicant:  SPIRENT COMMUNICATIONS PLC
Name of scheme:     SPIRENT GLOBAL ALL EMPLOYEE SHARE PURCHASE PLAN
Period of return:   From: 1 JULY 2006        To: 31 DECEMBER 2006
Balance under scheme from previous  814,444 ORDINARY SHARES OF 3 1/3p
return:                             EACH
The amount by which the block       NIL
scheme has been increased, if the
scheme has been increased since the
date of the last return:
Number of securities issued/        NIL
allotted under scheme during
period:
Balance under scheme not yet issued 814,444 ORDINARY SHARES OF 3 1/3p
/allotted at end of period:         EACH
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 975,851,486 ORDINARY SHARES OF 
at the end of the period :          3 1/3p EACH (885,599,999 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: 9 January 2007


Name of applicant:  SPIRENT COMMUNICATIONS PLC
Name of scheme:     NETCOM AMENDED AND RESTATED STOCK OPTION PLAN
Period of return:   From: 1 JULY 2006        To: 31 DECEMBER 2006
Balance under scheme from previous  1,526,887 ORDINARY SHARES OF 3 1/3p
return:                             EACH
The amount by which the block       2,500,000 ORDINARY SHARES OF 3 1/3p
scheme has been increased, if the   EACH
scheme has been increased since the
date of the last return:
Number of securities issued/        966,154 ORDINARY SHARES OF 3 1/3p
allotted under scheme during        EACH
period:
Balance under scheme not yet issued 3,060,733 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 1/3p 
                                    EACH DATED 8 JULY 2002

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

                                    2,500,000 ORDINARY SHARES OF 3 1/3p 
                                    EACH DATED 19 OCTOBER 2006
Total number of securities in issue 975,851,486 ORDINARY SHARES OF 
at the end of the period :          3 1/3p EACH (885,599,999 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: 9 January 2007


Name of applicant:  SPIRENT COMMUNICATIONS PLC
Name of scheme:     ZARAK AMENDED AND RESTATED STOCK OPTION PLAN
Period of return:   From: 1 JULY 2006        To: 31 DECEMBER 2006
Balance under scheme from previous  2,690,996 ORDINARY SHARES OF 3 1/3p
return:                             EACH
The amount by which the block       NIL
scheme has been increased, if the
scheme has been increased since the
date of the last return:
Number of securities issued/        NIL
allotted 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      3,895,474 ORDINARY SHARES OF 3 1/3p
originally listed and the date of   EACH DATED 14 NOVEMBER 2000
admission:
Total number of securities in issue 975,851,486 ORDINARY SHARES OF 
at the end of the period :          3 1/3p EACH (885,599,999 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: 9 January 2007


Name of applicant:  SPIRENT COMMUNICATIONS PLC
Name of scheme:     SPIRENT SAVINGS RELATED SHARE OPTION SCHEME
Period of return:   From: 1 JULY 2006        To: 31 DECEMBER 2006
Balance under scheme from previous  68,185 ORDINARY SHARES OF 3 1/3p
return:                             EACH
The amount by which the block       NIL
scheme has been increased, if the
scheme has been increased since the
date of the last return:
Number of securities issued/        NIL
allotted under scheme during
period:
Balance under scheme not yet issued 68,185 ORDINARY SHARES OF 3 1/3p
/allotted at end of period:         EACH
Number and class of securities      200,000 ORDINARY SHARES OF 3 1/3p
originally listed and the date of   EACH DATED 31 DECEMBER 2003
admission:
Total number of securities in issue 975,851,486 ORDINARY SHARES OF
at the end of the period :          3 1/3p EACH (885,599,999 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: 9 January 2007


Name of applicant:  SPIRENT COMMUNICATIONS PLC
Name of scheme:     SPIRENT STOCK INCENTIVE PLAN
Period of return:   From: 1 JULY 2006        To: 31 DECEMBER 2006
Balance under scheme from previous  3,863,831 ORDINARY SHARES OF 3 1/3p
return:                             EACH
The amount by which the block       NIL
scheme has been increased, if the
scheme has been increased since the
date of the last return:
Number of securities issued/        1,877,635 ORDINARY SHARES OF 3 1/3p
allotted under scheme during        EACH
period:
Balance under scheme not yet issued 1,986,196 ORDINARY SHARES OF 3 1/3p
/allotted at end of period:         EACH
Number and class of securities      3,720,930 ORDINARY SHARES OF 3 1/3p
originally listed and the date of   EACH DATED 1 OCTOBER 2003
admission:

                                    3,703,703 ORDINARY SHARES OF 3 1/3p 
                                    EACH DATED 2 OCTOBER 2003
Total number of securities in issue 975,851,486 ORDINARY SHARES OF 
at the end of the period :          3 1/3 p EACH (885,599,999 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: 9 January 2007


Name of applicant:  SPIRENT COMMUNICATIONS PLC
Name of scheme:     CAW AMENDED AND RESTATED STOCK OPTION PLAN
Period of return:   From: 1 JULY 2006        To: 31 DECEMBER 2006
Balance under scheme from previous  833,485 ORDINARY SHARES OF 3 1/3p
return:                             EACH
The amount by which the block       NIL
scheme has been increased, if the
scheme has been increased since the
date of the last return:
Number of securities issued/        18,365 ORDINARY SHARES OF 3 1/3p
allotted under scheme during        EACH
period:
Balance under scheme not yet issued 815,120 ORDINARY SHARES OF 3 1/3p
/allotted at end of period:         EACH
Number and class of securities      1,300,000 ORDINARY SHARES OF 3 1/3p
originally listed and the date of   EACH DATED 15 AUGUST 2002
admission:
                                    115,394 ORDINARY SHARES OF 3 1/3 p
                                    EACH DATED 28 AUGUST 2002
Total number of securities in issue 975,851,486 ORDINARY SHARES OF 
at the end of the period :          3 1/3p EACH (885,599,999 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.

                This information is provided by RNS
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