FOURTH QUARTER TRADING UPDATE

Spirent Communications PLC
13 December 2007



                               SPIRENT COMMUNICATIONS PLC

                             FOURTH QUARTER TRADING UPDATE



London, UK - 13 December 2007: Spirent Communications plc ("Spirent" or "the
Company") (LSE: SPT), a leading communications technology company, today
announces a trading update for the quarter ended 31 December 2007.



Trading update

Based on trading during the fourth quarter to date the Company anticipates that
results for the second half year as a whole will be somewhat ahead of expected
levels.



Financial position

The Company continued the buyback of shares, with £39.3 million of cash being
returned through share buybacks in the quarter to date, a further purchase of
59.5 million shares by the Company.

The preliminary results for the year ending 31 December 2007 are expected to be
announced to shareholders on 28 February 2008.



                                    - ends -



Enquiries
Edward Bramson, Executive Chairman           Spirent Communications plc        [phone]
Eric Hutchinson, Chief Financial Officer
Andrew Dowler/Harriet Keen                   Financial Dynamics                [phone]



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 ("OTC") 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.



Cautionary statement

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 this document,
whether as a result of new information, future events or otherwise.




                      This information is provided by RNS
            The company news service from the London Stock Exchange