Spirent Communications PLC - Holding(s) in Company


Crawley, UK -- (MARKET WIRE) -- May 22, 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 the notification (please tick the appropriate box or boxes)

An acquisition or disposal of voting rights - DISPOSAL                          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 the    (i) Lexa BV
notification obligation:
                                            (ii) Goran Ennerfelt (a
                                            non-executive director of
                                            Spirent Communications
                                            plc) has a connected interest
                                            in the shareholding of Lexa
                                            BV. This is due to the
                                            fact that he is President and
                                            Chief Executive Officer
                                            of Axel Johnson AB, a member
                                            of the Axel Johnson Group
                                            which owns Lexa BV.

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

5. Date of the transaction (and date on 
which the threshold is crossed or reached if different):                                 22 May 2007

6. Date on which issuer notified:           22 May 2007

7. Threshold(s) that is/are crossed or reached:                                    Below 10 %

8. Notified details:                        Sold 40,400,000 Ordinary
                                            shares

A: Voting rights attached to shares

Class/type of     Situation previous to    Resulting situation after the triggering transaction
shares            the Triggering
                  transaction
 if possible      Number of    Number of   Number of     Number of voting rights ix  % of voting rights
using the ISIN    Shares       Voting      shares
CODE                           Rights viii Direct        Direct  x   Indirect xi     Direct     Indirect

Ordinary shares   90,400,000   90,400,000   50,000,000   50,000,000        N/A          5.67       N/A

ISIN:
GB0004726096

B: Financial Instruments

Resulting situation after the triggering transaction
Type of financial  Expiration date Exercise/ Conversion      Number of voting rights    % of voting
instrument                           Period/ Date              that may be acquired if    rights
                                                               the instrument is
                                                               exercised/ converted.

        N/A                N/A                  N/A                       N/A                   N/A


Total (A+B)
Number of voting rights              % of voting rights
50,000,000                           5.67%


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

(i) Lexa BV

(ii) Goran Ennerfelt (a non-executive director of Spirent Communications
plc) has a connected interest in the shareholding of Lexa BV. This is due
to the fact that he is President and Chief Executive Officer of Axel
Johnson AB, a member of the Axel Johnson Group which owns Lexa BV.

Proxy Voting:

10. Name of the proxy holder:                            N/A

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

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

13. Additional information:                              N/A

14. Contact name:                Arie Bouman - Managing Director, LEXA BV

15. Contact telephone number:    +31 (0)20 471 3438

C:        Additional information

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

Telephone: 01293 767676


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