Transaction in Own Shares

Spirent Communications PLC
09 November 2007

                           SPIRENT COMMUNICATIONS PLC



                           TRANSACTION IN OWN SHARES



London, UK - 9 November 2007: Spirent Communications plc ("the Company") (LSE:
SPT), a leading communications technology company announces that it has today
purchased through UBS Limited 16,200,000 ordinary shares at a price of 69.00
pence per share.



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



Following the purchase of these shares, Spirent Communications plc holds
60,382,103 of its ordinary shares in treasury and has 829,996,805 ordinary
shares in issue (excluding treasury shares).  This figure (829,996,805)
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.





                                    - ends -



Enquiries
Eric Hutchinson           Spirent Communications plc         [phone]
Chief Financial Officer





About Spirent Communications plc



Spirent Communications plc is a leading communications technology company
focused on delivering innovative systems and services to meet the needs of
customers worldwide.  We are a global provider of performance analysis and
service assurance solutions that enable the development and deployment of
next-generation networking technologies such as broadband services, Internet
telephony, 3G wireless and web applications and security testing.  The Systems
group develops power control systems for specialist electrical vehicles in the
mobility and industrial markets.  Further information about Spirent
Communications plc can be found at www.spirent.com.



Spirent Communications plc Ordinary shares are traded on the London Stock
Exchange (ticker: SPT).  The Company operates a Level 1 American Depositary
Receipt ("ADR") programme with each ADR representing four Spirent Communications
plc Ordinary shares.  The ADRs trade in the US over-the-counter market under the
symbol SPMYY and the CUSIP number is 84856M209.



Spirent and the Spirent logo are trademarks or registered trademarks of Spirent
Communications plc.  All other trademarks or registered trademarks mentioned
herein are held by their respective companies.  All rights reserved.



This document may contain forward-looking statements which are made in good
faith and are based on current expectations or beliefs, as well as assumptions
about future events.  You can sometimes, but not always, identify these
statements by the use of a date in the future or such words as "will", "
anticipate", "estimate", "expect", "project", "intend", "plan", "should", "may",
"assume" and other similar words.  By their nature, forward-looking statements
are inherently predictive and speculative and involve risk and uncertainty
because they relate to events and depend on circumstances that will occur in the
future.  You should not place undue reliance on these forward-looking
statements, which are not a guarantee of future performance and are subject to
factors that could cause our actual results to differ materially from those
expressed or implied by these statements.  The Company undertakes no obligation
to update any forward-looking statements contained in those document, whether as
a result of new information, future events or otherwise.






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