Holding(s) in Company

Spirent Communications PLC
14 March 2007


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

1. Identity of the issuer or the underlying issuer of existing      Spirent Communications plc
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                                                
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): Initial notification pursuant to Transitional Provision 7               X

                                     Of the Disclosure and Transparency Rules
3. Full name of person(s) subject to the notification          (i) Sherborne Investors GP, LLC
obligation(iii):
                                                               (ii) Sherborne Investors LP

                                                               (iii) Craig L. McKibben

                                                               (iv) Gerard L. Eastman, Jr.

                                                               (v) Hayden Investors Partners,

                                                                     LLC

                                                               (vi) Hayden Investors Partners II,

                                                                      LLC

                                                               (vii) Sherborne Strategic Fund A,

                                                                       LLC (formerly Hanover

                                                                       Strategic Fund A, LLC)



                                                                       (viii) Edward Bramson
4. Full name of shareholder(s) (if different from 3.)(iv):                  Noted below
Persons named in 3 above   Shareholder                               No of Shares

(i) to (iv)                              Hanover Nominees Limited      130,250,000 ordinary shares
(aggregate)

(v)                                        Hanover Nominees Limited      45,685,845 ordinary shares

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

(vii)                                      Hanover Nominees Limited       29,644,000 ordinary shares

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

                                              (b) Merrill Lynch, Pierce,          20,000 ordinary shares

                                                    Fenner & Smith, Inc.
5. Date of the transaction (and date on which the threshold is                  N/A
crossed or reached if different)(v):
6. Date on which issuer notified:                                         March 13, 2007
7. Threshold(s) that is/are crossed or reached:                 (i) Sherborne Investors GP, LLC - 14%
                                                               (aggregate)

                                                               (ii)     Sherborne Investors LP - 14%
                                                               (aggregate)

                                                               (iii) Craig L. McKibben - 14% (aggregate)

                                                               (iv) Gerard L. Eastman, Jr - 14%
                                                               (aggregate)

                                                               (v) Hayden Investors Partners, LLC - 5%

                                                               (vi) Hayden Investors Partners II, LLC -
                                                               4%

                                                               (vii) Sherborne Strategic Fund A, LLC -
                                                               3%

                                                               (viii) Edward Bramson - 14% (aggregate)
8. Notified details:


A: Voting rights attached to shares
Class/type of     Situation previous to the Resulting situation after the triggering transaction(vii)
shares            Triggering transaction
                  (vi)
 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   130,250,000  130,250,000                     N/A    130,250,000     N/A       14.7%
                                            130,250,000
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 xii
Type of financial    Expiration date Exercise/ Conversion      Number of voting rights    % of voting
instrument           xiii            Period/ Date xiv          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
     130,270,000                                   14.7%




9. Chain of controlled undertakings through which the voting rights and/or the financial instruments are effectively
held, if applicable xv:
Edward Bramson, 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 5.15%);

(ii)                Hayden Investors Partners II, LLC (40,844,268 ordinary shares - approximately 4.61%);

(iii)               Sherborne Strategic Fund A, LLC (29,644,000 ordinary shares - approximately 3.34%);

(iv)              Sherborne Strategic Fund B, LLC (formerly Hanover Strategic Fund B, LLC, 14,075,887 ordinary shares -
no individual notification obligation)

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


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           N/A
rights:
13. Additional information:                 N/A


14. Contact name:                               Craig L. McKibben
15. Contact telephone number:                   [phone]

C:        Additional information
Contact at Issuer:           Michael Anscombe (Deputy Company Secretary)

                                     Spirent Communications plc

Telephone:                     01293 767676












--------------------------


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.



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