Holding(s) in Company

Spirent Communications PLC
04 December 2007




TR-1: Notification of Major Interests in Shares

Spirent Communications plc


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


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): Decrease in the number of total voting rights in       X
Spirent Communications plc resulting from the on-going share 
buy-back programme



                                                                         

3. Full name of person(s) subject to notification obligation:                 
                                                                         
(i) Hayden Investors Partners II, LLC;
(ii) Sherborne Investors LP;
(iii) Sherborne Investors GP, LLC;
(iv) Craig L. McKibben;
(v) Gerard L Eastman, Jr; and
(vi) Edward Bramson.

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

Noted below

Person named in 3 above      Shareholder                         No of shares

(i)                          Hanover Nominees Limited            40,844,268 ordinary shares

(ii) - (v)                   Hanover Nominees Limited            130,250,000 ordinary shares
                                                                 (aggregate)

(vi)                         (a) Hanover Nominees Limited        130,250,000 ordinary shares
                                                                 (aggregate)

                             (b) Merrill Lynch, Pierce, Fenner   20,000 ordinary shares
                                 & Smith, Inc

                                                                   
5. Date of transaction (and date on which the threshold is
crossed or reached if different):
                                                                                    
December 3, 2007 (being the date of the most recent
TVR announcement)


6. Date on which issuer notified:

December 3, 2007

                                                                

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

(i) Hayden Investors Partners II, LLC - 5%;
(ii) Sherborne Investors LP - 16% (aggregate);
(iii) Sherborne Investors GP, LLC - 16% (aggregate);
(iv) Craig L. McKibben - 16% (aggregate);
(v) Gerard L Eastman, Jr - 16% (aggregate); and
(vi) Edward Bramson - 16% (aggregate).


Please note, for the purposes of this TR-1
notification the only entities who have triggered
a new notification obligation under the Disclosure
and Transparency Rules are those entities noted in
3 above.  None of Hayden Investors Partners, LLC;
Sherborne Strategic Fund A, LLC or Sherborne
Strategic Fund B, LLC have reached, exceeded or
fallen below a relevant threshold as a result of
Spirent Communications plc's recent buy-back
programme.


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 rights shares                                   rights
ISIN code
                                              Direct        Direct       Indirect      Direct      Indirect

 Ordinary shares   130,250,000   130,250,000   130,250,000      N/A       130,250,000      N/A        16.07%



ISIN: GB0004726096
 Ordinary shares      20,000       20,000        20,000        20,000         N/A        0.002%        N/A
ISIN: 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

130,270,000 (aggregate)                              16.08%


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


Edward Bramson is the managing member and Craig L. McKibben and Gerard L. Eastman, Jr. are members of Sherborne
Investors GP, LLC.  Sherborne Investors GP, LLC is the general partner of Sherborne Investors LP, which is the managing
member of each of the following funds (all of which hold ordinary shares in the issuer through Hanover Nominees
Limited):
     
(i)  Hayden Investors Partners, LLC (45,685,845 ordinary shares - approximately 
     5.64% -no new individual notification required, see response to 7 above);

(ii) Hayden Investors Partners II, LLC (40,844,268 ordinary shares - 
     approximately 5.04% - such figure being a subject of this notification of 
     major interests in shares);

(iii)Sherborne Strategic Fund A, LLC (29,644,000 ordinary shares - approximately 
     3.66% -  no new individual notification required, see response to 7 above); 
     and

(iv) Sherborne Strategic Fund B, LLC (14,075,887 ordinary shares - approximately 
     1.74% - no individual notification required, see response to 7 above).

Edward Bramson holds 20,000 further shares through Merrill Lynch, Pierce, 
Fenner & Smith, Inc.


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:                          N/A

14 Contact name:                                     Craig L. McKibben

15. Contact telephone name:                          [phone]


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