Holding(s) in Company

Spirent Communications PLC
07 May 2008




TR-1: Notification of Major Interests in Shares


                                                                    
1. Identity of the issuer or the underlying issuer of
existing shares to which voting rights are attached:                Spirent Communications plc



2. Reason for notification (yes/no)
                                                                                              

An acquisition or disposal of voting rights                         X


An acquisition or disposal of financial instruments which may result in the acquisition
of shares already issued to which voting rights are attached


An event changing the breakdown of voting rights


Other (please specify):______________
                                                               

3. Full name of person(s) subject to notification
obligation:                                          Aviva plc & its subsidiaries

                                                     Registered Holder:
4. Full name of shareholder(s) (if different from
3):                                                  BNY Norwich Union Nominees Limited
                                                     10,217,111*

                                                     Chase GA Group Nominees Limited
                                                     19,655,815*

                                                     Chase Nominees Limited
                                                     2,434,476*

                                                     CUIM Nominee Limited
                                                     6,042,364*

                                                     Vidacos Nominees Limited
                                                     115,489*

                                                     * denotes direct interest

                                                     Chase Nominees Limited
                                                     3,708,517

                                                     Vidacos Nominees Limited
                                                     5,808,645

                                                                     

5. Date of transaction (and date on which the
threshold is crossed or reached if different):       02 May 2008
                                                                      

6. Date on which issuer notified:                    06 May 2008
                                                         

7. Threshold(s) that is/are crossed or reached:      4% to 5% Change at Direct Interest Level


8. Notified Details
A: Voting rights attached to shares


Class/type of     Situation previous to the Resulting situation after the triggering transaction
shares            triggering transaction
                  Number of    Number of    Number of    Number of voting rights Percentage of voting
If possible use   shares       voting       shares                               rights
ISIN code                      rights

                                            Direct       Direct      Indirect    Direct      Indirect
                   48,648,876   48,648,876   38,465,255  38,465,255   9,517,162     5.08%       1.26%
Ordinary Shares
GB0004726096


B: Financial Instruments


Resulting situation after the triggering transaction


Type of financial   Expiration date     Exercise/           No. of voting rights that Percentage of
instrument                              conversion period/  may be acquired (if the   voting rights
                                        date                instrument is exercised/
                                                            converted)
        N/A              N/A            N/A                 N/A                       N/A




Total (A+B)


Number of voting rights                              Percentage of voting rights
       47,982,417                                             6.34%


9. Chain of controlled undertakings through which the voting rights and /or the financial instruments are effectively
held, if applicable:


See Section 4







Proxy Voting:


10. Name of proxy holder:                            See Section 4


11. Number of voting rights proxy holder will cease
to hold:


12. Date on which proxy holder will cease to hold
voting rights:


13. Additional information:                          Figures are based on a total number of voting rights
                                                     of 756,852,333


14 Contact name:                                     Neil Whittaker


15. Contact telephone name:                          01603 684420






Additional information
Contact at Issuer: Michael Anscombe, Company Secretary, Spirent Communications plc

Telephone: [phone]






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