Holding(s) in Company

Spirent PLC
19 December 2005


                   NOTIFICATION OF MAJOR INTERESTS IN SHARES


1. Name of listed company


SPIRENT PLC



2. Name of shareholder with a major interest


PRUDENTIAL PLC



3. Please state whether notification indicates that regarding the holding of the
shareholder named in 2 above; in respect of a non-beneficial interest; or in the
case of an individual holder if it is a holding of that person's spouse or
children under the age of 18


SHAREHOLDER IN 2 ABOVE



4. Name of the registered holder(s) and, if more than one holder, the number of
shares held by each of them


MAGIM HSBC GIS NOM (UK) SALI                                             566,983

PRUCLT HSBC GIS NOM (UK) PAC AC                                       24,770,187

PRUCLT HSBC GIS NOM (UK) PPL AC                                        5,110,568

PRUCLT HSBC GIS NOM (UK) EQBF AC                                         270,027

PRUCLT HSBC GIS NOM (UK) MNBF AC                                         459,959

PRUCLT HSBC GIS NOM (UK) PENE AC                                       1,702,386

TOTAL                                                                 32,880,110


5. Number of shares / amount of stock acquired


NOT KNOWN



6. Percentage of issued class (any treasury shares held by the listed company
should not be taken into account when calculating percentage)


NOT KNOWN




7. Number of shares / amount of stock disposed


-



8. Percentage of issued class (any treasury shares held by the listed company
should not be taken into account when calculating percentage)


-



9. Class of security


ORDINARY SHARES OF 3.3333 PENCE EACH



10. Date of transaction


NOT NOTIFIED



11. Date company informed


16 DECEMBER 2005





12. Total holding following this notification


32,880,110



13. Total percentage holding of issued class following this notification (any
treasury shares held by the listed company should not be taken into account when
calculating percentage)


3.4%



14. Any additional information


SHAREHOLDER PREVIOUSLY REPORTED THAT IT NO LONGER HELD A NOTIFIABLE INTEREST IN
THE COMPANY ON 21 JANUARY 2004



15. Name of contact and telephone number for queries


LUKE THOMAS - 01293 767658



16. Name and signature of duly authorised company official of the listed company
responsible for making this notification


LUKE THOMAS - DEPUTY COMPANY SECRETARY



Date of notification


19 DECEMBER 2005


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