Treasury Share Cancellation

Spirent Communications PLC
05 October 2007



                           SPIRENT COMMUNICATIONS PLC

                    CANCELLATION OF SHARES HELD IN TREASURY


London, UK - 5 October 2007: Spirent Communications plc ("the Company") (LSE:
SPT), a leading communications technology company would like to notify the
market in accordance with Listing Rule 12.6.4R, of the following information:


The Company has today cancelled 75,000,000 ordinary shares each with a nominal
value of 3 1/3 pence currently held in Treasury.  Following the
cancellation of shares held in Treasury, the Company's issued share capital
consists of 890,039,316 ordinary shares of 3 1/3 pence. The Company now
holds 30,534,172 ordinary shares in Treasury, and the Company is not permitted
to exercise voting rights in respect of those ordinary shares. Therefore, the
total number of voting rights in the Company is 859,505,144.


The above figure (859,505,144) may be used by shareholders as the denominator
for the calculations by which they will determine if they are required to notify
their interest in, or a change to their interest in, the Company under the
Financial Services Authority Disclosure and Transparency Rules.


                                    - ends -


Enquiries
Michael Anscombe           Spirent Communications plc      [phone]
Company Secretary





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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