Crawley, UK -- (MARKET WIRE) -- October 13, 2006 --

The following amendment has been made to the 'Transaction in Own Shares' announcement released today at 17:05 under RNS No 4769K.

The shares in issue should read 902,212,613 and not 832,403,551 as previously shown.

All other details remain unchanged.

The full amended text is shown below.

Spirent Communications Plc

Transaction in Own Shares - Amendment

Spirent Communications PLC announces that it has today purchased through Citigroup Global Markets U.K. Equity Limited 1,000,000 ordinary shares at an average price of 59.611 pence per share. The highest price and the lowest price paid for these shares were 60.0 pence and 58.75 pence respectively.

Following the above purchase, Spirent Communications plc holds 70,790,000 Spirent Communications plc ordinary shares in treasury, and has 902,212,613 Spirent Communications plc ordinary shares in issue (excluding treasury shares).

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