Holding(s) in Company

Spirent Communications PLC
13 November 2007




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
                                                     

4. Full name of shareholder(s) (if different from    Registered Holder:
3):
                                                     BNY Norwich Union Nominees Limited
                                                                    8,794,796*

                                                     Chase GA Group Nominees Limited
                                                                   18,384,404*

                                                     Chase Nominees Limited
                                                                    2,456,022*

                                                     CUIM Nominee Limited
                                                                    6,568,047*

                                                     Vidacos Nominees Limited
                                                                      154,729*


                                                     * denotes direct interest

                                                     Chase Nominees Limited
                                                                    3,681,820

                                                     CUIM Nominee Limited
                                                                      723,070

                                                     Vidacos Nominees Limited
                                                                    7,885,988


                                                                     

5. Date of transaction (and date on which the
threshold is crossed or reached if different):          09 November 2007
                                                                     

6. Date on which issuer notified:                       13 November 2007
                                                        

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

Ordinary Shares                              Direct       Direct      Indirect    Direct      Indirect
GB0004726096     38,048,985   38,048,985   36,357,998   36,357,998   12,290,878    4.39%       1.49%

 

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

    48,648,876                                             5.88%


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 827,741,456


14 Contact name:                                     Diane Thirkettle


15. Contact telephone name:                          01603 687803






Additional information
Contact at Issuer: Michelle Balch, Assistant Company Secretary, Spirent Communications plc

Telephone: [phone]






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