Spirent Communications PLC announces Holding(s) in Company 2


Crawley, UK -- (MARKET WIRE) -- May 25, 2007 --


TR-1(i): NOTIFICATION OF MAJOR INTERESTS IN SHARES - 2

1. Identity of the issuer or the          Spirent Communications plc
   underlying issuer of existing 
   shares to which voting rights 
   are attached (ii):

2. Reason for the notification 
   (please tick the appropriate 
   box or boxes

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 the  Lehman Brothers International
   notification obligation(1)(iii):       (Europe)

4. Full name of shareholder(s) (if                         N/A
   different from 3.)(1)(iv):                        

5. Date of the transaction (and date on                22 May 2007
   which the threshold is crossed or reached         if different)(1)(v):

6. Date on which issuer notified:                      24 May 2007

7. Threshold(s) that is/are crossed
   or reached:                                               4%

8. Notified details:                                      N/A


A: Voting rights attached to shares
Class/type of shares        Situation previous to the Triggering transaction (vi)
if possible using the ISIN
CODE
                            Number of Shares   Number of Voting Rights viii

    Ordinary Shares           34,174,456             34,174,456
     GB0004726096

A: Voting rights attached to shares
Class/type of   Resulting situation after the triggering transaction(vii)
if possible     
using the 
ISIN CODE
                 Number of   Number of voting rights   % of voting rights
                 shares      ix
                 Direct      Direct x       Indirect   Direct    Indirect
                                                 xi
Ordinary Shares  35,736,167  35,736,167      N/A        4.06%       N/A
   GB0004726096

B: Financial Instruments

Resulting situation after the triggering transaction xii

Type of        Expiration  Exercise/
financial      date xiii   Conversion Period/
instrument                 Date xiv
                                      N/A

B: Financial Instruments

Resulting situation after the triggering transaction xii

Number of voting rights    % of
that may be acquired if    voting
the instrument is          rights
exercised/ converted.



Total (A+B)
Number of voting rights                 % of voting rights
                                
35,736,167                              4.06%

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

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:                                     Tara O'Hagan
15. Contact telephone number:                         +44 (0) 20 7102 1832

C: Additional information

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

Telephone: 01293 767672


NOTES:
    
(i)  This form is to be sent to the issuer or underlying issuer and to
     be filed with the competent authority.

(ii) Either the full name of the legal entity or another method for
     identifying the issuer or underlying issuer, provided it is reliable 
     and accurate.

(iii)This should be the full name of (a) the shareholder; (b) the
     person acquiring, disposing of or exercising voting rights in the 
     cases provided for in DTR5.2.1 (b) to (h);  (c) all the parties to 
     the agreement referred to in DTR5.2.1 (a), or (d) the direct or 
     indirect holder of financial instruments entitled to acquire shares 
     already issued to which voting rights are attached, as appropriate.
     In relation to the transactions referred to in points DTR5.2.1 (b) 
     to (h), the following list is provided as indication of the persons 
     who should be mentioned:

-    in the circumstances foreseen in  DTR5.2.1 (b), the person that
     acquires the voting rights and is entitled to exercise them under 
     the agreement and the natural person or legal entity who is 
     transferring temporarily for consideration the voting rights;

-    in the circumstances foreseen in DTR 5.2.1 (c), the person holding
     the collateral, provided the person or entity controls the voting 
     rights and declares its intention of exercising them, and person 
     lodging the collateral under these conditions;

-    in the circumstances foreseen in DTR5.2.1(d), the person who has a
     life interest in shares if that person is entitled to exercise the 
     voting rights attached to the shares and the person who is disposing 
     of the voting rights when the life interest is created;

-    in the circumstances foreseen in DTR5.2.1 (e), the parent 
     undertaking and, provided it has a notification duty at an 
     individual level under DTR 5.1, under DTR5.2.1 (a) to (d) or under a 
     combination of any of those situations, the controlled undertaking;

-    in the circumstances foreseen in DTR5.2.1 (f), the deposit taker of
     the shares, if he can exercise the voting rights attached to the 
     shares deposited with him at his discretion, and the depositor of 
     the shares allowing the deposit taker to exercise the voting rights 
     at his discretion;

-    in the circumstances foreseen in DTR5.2.1 (g), the person  that
     controls the voting rights; 

-    in the circumstances foreseen in DTR5.2.1 (h), the proxy holder, if
     he can exercise the voting rights at his discretion, and the 
     shareholder who has given his proxy to the proxy holder allowing the 
     latter to exercise the voting rights at his discretion.

(iv) Applicable in the cases provided for in DTR 5.2.1 (b) to (h). This
     should be the full name of the shareholder or holder of financial 
     instruments who is the counterparty to the natural person or legal 
     entity referred to in DTR5.2.

(v)  The date of the transaction should normally be, in the case of an
     on exchange transaction, the date on which the matching of orders 
     occurs; in the case of an off exchange transaction, date of the 
     entering into an agreement.

The date on which threshold is crossed should normally be the date on 
which the acquisition, disposal or possibility to exercise voting rights 
takes effect (see DTR 5.1.1R (3)). For passive crossings, the date when 
the corporate event took effect.

These dates will usually be the same unless the transaction is subject to
a condition beyond the control of the parties. 

(vi)  Please refer to the situation disclosed in the previous
      notification, In case the situation previous to the triggering 
      transaction was below 3%, please state 'below 3%'.

vii   If the holding has fallen below the minimum threshold , the
      notifying party should not be obliged to disclose the extent of the 
      holding, only that the new holding is less than 3%.

For the case provided for in DTR5.2.1(a), there should be no disclosure of
individual holdings per party to the agreement unless a party individually
crosses or reaches an Article 9 threshold. This applies upon entering 
into, introducing changes to or terminating an agreement.

viii  Direct and indirect

ix    In case of combined holdings of shares with voting rights attached '
      direct holding' and voting rights 'indirect holdings', please split 
      the voting rights number and percentage into the direct and 
      indirect columns-if there is no combined holdings, please leave the 
      relevant box blank.

X     Voting rights attached to shares in respect of which the notifying
      party is a direct shareholder  (DTR 5.1)

xi    Voting rights held by the notifying party as an indirect
      shareholder (DTR 5.2.1)

xii   If the holding has fallen below the minimum threshold, the notifying
      party should not be obliged to disclose the extent of the holding, 
      only that the new holding is below 3%.

xiii  date of maturity / expiration of the finical instrument i.e. the
      date when the right to acquire shares ends.

xiv   If the financial instrument has such a period-please specify the
      period- for example once every three months starting from the (date)

xv    The notification should include the name(s) of the controlled
      undertakings through which the voting rights are held. The 
      notification should also include the amount of voting rights and 
      the percentage held by each controlled undertaking, insofar as 
      individually the controlled undertaking holds 3% or more, and 
      insofar as the notification by the parent undertaking is 
      intended to cover the notification obligations of the controlled 
      undertaking.

xvi   This annex is only to be filed with the competent authority.

xvii  Whenever another person makes the notification on behalf of the
      shareholder or the natural person/legal entity  referred to in 
      DTR5.2 and DTR5.3. 

**************************************************************************


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