Holding(s) in Company

RNS Number : 6155J

Spirent Communications PLC

05 December 2008

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		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 notification obligation:	Sun Life Assurance Company of Canada (UK) Ltd
4. Full name of shareholder(s) (if different from 3.):	ROY Nominees Limited
5. Date of the transaction (and date on which the threshold is crossed or reached if different):	03-12-2008
6. Date on which issuer notified:	04-12-2008
7. Threshold(s) that is/are crossed or reached:	4%
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 rights		% of voting rights
			Direct	Direct	Indirect	Direct	Indirect
GB0004726096	35,450,812	35,450,812	23,382,347	23,382,347		3.46

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

Total (A+B)

Number of voting rights

% of voting rights

23,382,347

3.46

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

Credit Suisse Asset Management Limited is a segregated business unit within Credit Suisse Group (CSG) with an independent management structure and exercises its voting rights independently from other parts of CSG.

Proxy Voting:
10. Name of the proxy holder:
11. Number of voting rights proxy holder will cease to hold:
12. Date on which proxy holder will cease to hold voting rights: