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

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

X

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

An event changing the breakdown of voting rights

Other (please specify):

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

Prudential plc group of companies

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

Prudential plc

The Prudential Assurance Company Limited

M&G Group Limited

M&G Limited

M&G Investment Management Limited

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

04 April 2017

6. Date on which issuer notified:

05 April 2017

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

See item 13

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

ORD GBP0.03333

GB0004726096

61,099,534

61,099,534

61,705,268

0

61,705,268

0

10.08%

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

ORD GBP0.03333

GB0004726096

(Right of Recall)

104,349

0.02%

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

Nominal

Delta

Total (A+B+C)

Number of voting rights

Percentage of voting rights

61,809,617

10.10%

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

Prudential plc (parent Company) - 61,809,617 (10.10%)

The Prudential Assurance Company Limited (wholly owned subsidiary of Prudential plc) - 50,689,156 (8.28%)

M&G Group Limited (wholly owned subsidiary of Prudential plc) - 61,809,617 (10.10%)

M&G Limited (wholly owned subsidiary of M&G Group Limited) - 61,809,617 (10.10%)

M&G Investment Management Limited (wholly owned subsidiary of M&G Limited) - 61,809,617 (10.10%)

Proxy Voting:

10. Name of the proxy holder:

N/A

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

N/A

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

N/A

13. Additional information:

Prudential plc has moved from 9% to a 10% indirect notifiable interest excluding the right of recall under the Qualifying Financial Instruments.

14. Contact name:

Owen Smith / John Baker

M&G Investment Management Limited

15. Contact telephone number:

020 7004 4517 / 020 7548 2561

C: Additional information

Contact at Issuer: Michelle Balch, Deputy Company Secretary, Spirent Communications plc

Telephone: 01293 767676