Holding(s) in Company

TR-1: NOTIFICATION OF MAJOR INTEREST IN SHARES

1. Identity of the issuer or the underlying issuerof existing shares to which voting rights areattached: ii

Spirent Communications plc

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

An acquisition or disposal of voting rights

Yes

An acquisition or disposal of qualifying financial instruments which may result in the acquisition of shares already issued to which voting rights are attached

No

An acquisition or disposal of instruments with similar economic effect to qualifying financial instruments

No

An event changing the breakdown of voting rights

No

Other (please specify):

No

3. Full name of person(s) subject to thenotification obligation: iii

Kames Capital

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

5. Date of the transaction and date onwhich the threshold is crossed orreached: v

08th November 2011

6. Date on which issuer notified:

10th November 2011

7. Threshold(s) that is/are crossed orreached: vi, vii

4%

8. Notified details:

A: Voting rights attached to shares viii, ix

Class/type ofshares

if possible usingthe ISIN CODE

Situation previousto the triggeringtransaction

Resulting situation after the triggering transaction

NumberofShares

NumberofVotingRights

Numberof shares

Number of votingrights

% of voting rights x

Direct

Direct xi

Indirect xii

Direct

Indirect

GB0004726096

26,933,062

26,933,062

24,040,494

24,040,494

1,728,826

3.57%

0.26%

B: Qualifying Financial Instruments

Resulting situation after the triggering transaction

Type of financialinstrument

Expirationdate xiii

Exercise/Conversion Period xiv

Number of votingrights that may beacquired if theinstrument isexercised/ converted.

% of votingrights

C: Financial Instruments with similar economic effect to Qualifying Financial Instruments xv, xvi

Resulting situation after the triggering transaction

Type of financialinstrument

Exercise price

Expiration date xvii

Exercise/Conversion period xviii

Number of voting rights instrument refers to

% of voting rights xix, xx

Contract for Difference

n/a

n/a

n/a

n/a

Nominal

Delta

0.00%

1

Total (A+B+C)

Number of voting rights

Percentage of voting rights

25,769,320

3.83%

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

Kames Capital:-

Kames Capital plcKames Capital Management LtdKames Capital ICVCKames Capital VCIC

Proxy Voting:

10. Name of the proxy holder:

Kames Capital

11. Number of voting rights proxy holder will ceaseto hold:

12. Date on which proxy holder will cease to holdvoting rights:

13. Additional information:

14. Contact name:

Wendy Dunsmore

15. Contact telephone number:

0131 549 3706

C: Additional information

Contact at Issuer: Rachel Whiting, Company Secretary, Spirent Communications plc

Telephone: 01293 767676