UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                   FORM 6-K

                        REPORT OF FOREIGN PRIVATE ISSUER
                       PURSUANT TO RULE 13a-16 OR 15d-16
                     UNDER THE SECURITIES EXCHANGE ACT OF 1934




                  For the month of September, 2003

                                 SPIRENT plc
     _____________________________________________________________________
                (Translation of registrant's name into English)

Spirent House, Crawley Business Quarter, Fleming Way, Crawley, West Sussex
RH10 9QL, UK.
     _____________________________________________________________________
                    (Address of principal executive offices)


Indicate by check mark whether the registrant files or will file annual reports
under cover Form 20-F or Form 40-F.

                         Form 20-F    X         Form 40-F.....

Indicate by check mark whether the registrant by furnishing the information
contained in this Form is also thereby furnishing the information to the
Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934.

                               Yes .....        No     X

If "Yes" is marked, indicate below the file number assigned to the registrant
in connection with Rule 12g3-2(b): 82- ________






Spirent plc.



Application has been made to The UK Listing Authority and the London Stock
Exchange for a block listing of 3,720,930 Ordinary shares of 3 1/3p each under
the Spirent Stock Option Plan, to trade on the London Stock Exchange and to be
admitted to the Official List upon issuance. The shares shall rank pari passu
with the existing issued shares of the Company.



Copies of this announcement are available from the office of Cazenove & Co. Ltd
for the period of 2 business days from the date hereof.



                                   Signatures

Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned, thereunto duly authorized.

                                               ______LUKE THOMAS______

                                                     (Registrant)

Date_30 September, 2003                   By   ____/s/ Luke Thomas____

                                                    (Signature)*