Transaction in Own Shares

Spirent Communications plc

Spirent Communications plc announces that it has put in place an irrevocable, non-discretionary programme allowing the buy back of Spirent Communications plc shares during the prohibited period which precedes the announcement of its half-year results for the half year ended 4 July 2010 on 5 August 2010.

Any purchases pursuant to these arrangements will be effected during the period between 5 July 2010 and the business day prior to the announcement of the half-year results above, within certain pre-set parameters and will be in accordance with the company's general authority to repurchase shares.

Any shares repurchased will be cancelled.