Holding(s) in Company

Spirent PLC
29 September 2004

                                  SCHEDULE 10

                   NOTIFICATION OF MAJOR INTERESTS IN SHARES



1. Name of company


SPIRENT PLC



2. Name of shareholder having a major interest


FIDELITY INTERNATIONAL LIMITED



3. Please state whether notification indicates that it is in respect of holding
of the shareholder named in 2 above or 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


COMPANY NAMED IN BOX 2 ABOVE AND ITS DIRECT AND INDIRECT SUBSIDIARIES, BEING NON-BENEFICIAL HOLDERS



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


CHASE MANHATTAN BANK LONDON TOTAL (FIL)                          443,649
DEUTSCHE BANK TOTAL (FIL)                                     37,476,297
NORTHERN TRUST TOTAL (FIL)                                       150,300
JP MORGAN TOTAL (FISL)                                           196,866

TOTAL                                                         38,267,112

FISL = Fidelity Investment Services Limited
FPM = Fidelity Pension Management
FIL = Fidelity International Limited



5. Number of shares / amount of stock acquired


NOT KNOWN



6. Percentage of issued class


NOT KNOWN



7. Number of shares / amount of stock disposed


-



8. Percentage of issued class


-



9. Class of security


ORDINARY SHARES OF 3.3333 PENCE EACH



10. Date of transaction


NOT NOTIFIED



11. Date company informed


29 SEPTEMBER 2004



12. Total holding following this notification


38,267,112



13. Total percentage holding of issued class following this notification


4.01%



14. Any additional information






15. Name of contact and telephone number for queries


LUKE THOMAS - 01293 767658



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


LUKE THOMAS - DEPUTY COMPANY SECRETARY



Date of notification


29 SEPTEMBER 2004



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