Holding(s) in Company

Spirent Communications PLC
25 January 2008


TR-1: Notification of Major Interests in Shares
                                                                    
1. Identity of the issuer or the underlying issuer of               Spirent Communications plc
existing shares to which voting rights are attached:

2. Reason for notification (yes/no)
                                                                                            
An acquisition or disposal of voting rights                                                  YES

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                     BlackRock, Inc
obligation:

4. Full name of shareholder(s) (if different from
3):                                                                   

5. Date of transaction (and date on which the
threshold is crossed or reached if different):                        22 January 2008

6. Date on which issuer notified:                                     24 January 2008
                                                                      
7. Threshold(s) that is/are crossed or reached:                       Gone below 5%




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    44,428,430   44,428,430      N/A          N/A     37,539,447      N/A         4.79%




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)





Total (A+B)


Number of voting rights                              Percentage of voting rights

37,539,447                                           4.79%




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

BlackRock Investment Management (UK) Limited - 37,539,447 (4.79%)




Proxy Voting:


10. Name of proxy holder:


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:


14 Contact name:                                     Thomas Hone
                                                     BlackRock, Inc

15. Contact telephone name:                          020 7743 2098



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

Telephone: [phone]






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