Transaction in Own Shares

Spirent Communications PLC
12 October 2007


Spirent Communications plc: Transaction in own shares

Spirent Communications plc announces that it has today purchased through UBS
Limited 513,270 ordinary shares at an average price of 65.7 pence per share. The
highest price and the lowest price paid for these shares were 66.0 pence and
65.25 pence respectively.

Spirent Communications plc intends to hold the purchased shares in treasury.

Following the purchase of these shares, Spirent Communications plc holds
33,535,725 of its ordinary shares in treasury and has 856,673,041 ordinary
shares in issue (excluding treasury shares).  This figure (856,673,041)
represents the total voting rights in the Company and may be used by
shareholders as the denominator for the calculations by which they can determine
if they are required to notify their interest in, or a change to their interest
in, the Company under the Financial Services Authority's Disclosure and
Transparency Rules.


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