Holding(s) in Company

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 

√

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 notification obligation:

Aviva plc & its subsidiaries

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

Registered Holder:

BNY Norwich Union Nominees Limited   9,789,601*

Chase GA Group Nominees Limited 26,761,015*

Chase Nominees Limited 2,424,366*

CUIM Nominee Limited 5,925,778*

Vidacos Nominees Limited 115,489*

* denotes direct interest

Chase Nominees Limited 2,077,774

Vidacos Nominees Limited 2,173,373

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

29 July 2008

6. Date on which issuer notified:

31 July 2008

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

5% to 6% Change at Direct Interest level 

8. Notified details:

A: Voting rights attached to shares

Class/type of shares 

 if possible using the ISIN CODE

Situation previous to the Triggering transaction

Resulting situation after the triggering transaction

Number of Shares 

Number of Voting Rights

Number of shares 

Number of voting right

% of voting rights

Direct

Direct

Indirect 

Direct

Indirect

Ordinary SharesGB0004726096

47,982,417

47,982,417

45,016,249

45,016,249

4,251,147

6.06%

 0.57%

B: Financial Instruments

Resulting situation after the triggering transaction 

Type of financial instrument 

Expiration date 

Exercise/ Conversion Period/ Date 

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

% of voting rights

N/A

Total (A+B)

Number of voting rights

% of voting rights

49,267,396

6.63%

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

See Section 4

Proxy Voting:

10. Name of the proxy holder:

See Section 4

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:

Figures are based on a total number of voting rights of 742,523,576.

14. Contact name:

Diane Thirkettle

15. Contact telephone number:

01603 687803

Additional information

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

Telephone: 01293 767676