Additional Listing

Spirent Communications PLC
10 July 2007

                           SPIRENT COMMUNICATIONS PLC



London, UK - 10 July 2007: Spirent Communications plc ("Spirent" or "the Company
") (LSE: SPT), application has been made to the Financial Services Authority and
the London Stock Exchange Plc for a total of 2,300,000 Ordinary shares of 3 
1/3p each in the capital of the Company ("shares") to be admitted to the
Official List and to trade.

It is expected that admission will be granted on 12 July 2007 and trading will
commence on 13 July 2007.

These shares are being reserved under a block listing and will be issued
pursuant to the Spirent Stock Incentive Plan.

When issued these shares will rank pari passu with the existing Ordinary shares.



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.



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