Holding(s) in Company

Spirent Communications PLC
10 September 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


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): A sale of shares has caused subsidiaries of Prudential plc to
cross 4% triggering this notification
                                                        X

                                                            

3. Full name of person(s) subject to notification
obligation:
                                                        Prudential plc group of companies

4. Full name of shareholder(s) (if different from       MAGIM HSBC GIS NOM(UK) SALI
3):
                                                        NORTRUST NOMINEE LTD A/C MHF01

                                                        NORTRUST NOMINEE LTD A/C MHJ01

                                                        NORTRUST NOMINEE LTD A/C MKM01

                                                        NORTRUST NOMS LTD

                                                        NORTRUST NOMS LTD A/C PUF01

                                                        NORTRUST NOMS LTD PUI01

                                                        NORTRUST NOMS LTD PUQ01

                                                        NORTRUST NOMS LTD PUR01

                                                        PRUCLT HSBC GIS NOM(UK) PAC AC

                                                        PRUCLT HSBC GIS NOM(UK) PPL AC

                                                        PRUCLT HSBC GIS NOM(UK) EQBF AC

                                                        PRUCLT HSBC GIS NOM(UK) MNBF AC

                                                        PRUCLT HSBC GIS NOM(UK) PENE AC


                                                                    

5. Date of transaction (and date on which the          05 September 2007
threshold is crossed or reached if different):
                                                                    

6. Date on which issuer notified:                      07 September 2007
                                                                       

7. Threshold(s) that is/are crossed or reached:        See item 13




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
 GB0004726096  65,846,110  65,846,110   71,146,110   71,146,110                 8.08%






B: Financial Instruments


Resulting situation after the triggering transaction


Type of financial    Expiration date      Exercise/ conversion No. of voting rights  Percentage of voting
instrument                                period/date          that may be acquired  rights
                                                               (if the 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
71,146,110                                           8.08%




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


Prudential plc (parent Company)

M&G Group Limited (wholly owned subsidiary of Prudential plc)

M&G Limited (wholly owned subsidiary of M&G Group Limited)

M&G Investment Management Limited (wholly owned subsidiary of M&G Limited)

The Prudential Assurance Company Limited (wholly owned subsidiary of Prudential plc)



Proxy Voting:


10. Name of proxy holder:                            N/A


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


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


13. Additional information:                          The Prudential Assurance Company Limited (a wholly
                                                     owned subsidiary of Prudential plc) has crossed a 4%
                                                     notifiable interest triggering this notification.


14 Contact name:                                     Emma Thompson



                                                     M&G Investment Management Limited


15. Contact telephone name:                          020 7548 2293






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

Telephone: [phone]






                      This information is provided by RNS
            The company news service from the London Stock Exchange   D

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