Holding(s) in Company

Spirent PLC
12 September 2005

                   NOTIFICATION OF MAJOR INTERESTS IN SHARES



1. Name of listed company


SPIRENT PLC



2. Name of shareholder with a major interest


FIDELITY INTERNATIONAL LIMITED



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 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


JP MORGAN BOURNEMOUTH (FPM)                                  6,253,714
NORTHERN TRUST LONDON (FPM)                                  4,312,500
STATE STR BK AND TR CO LNDN (FPM)                            3,448,249
BANK OF NEW YORK BRUSSELS (FPM)                              1,973,300
MELLON BANK (FPM)                                            1,651,600
BANKERS TRUST LONDON (FPM)                                     823,500
HSBC BANK PLC (FPM)                                            447,900
MIDLAND SECURITIES SERVICES (FPM)                              415,500
CLYDESDALE BANK PLC (FPM)                                      130,700
JP MORGAN BOURNEMOUTH (FISL)                                22,453,976
BROWN BROS HARRIMN LTD LUX (FIL)                            23,970,494
BANK OF NEW YORK BRUSSELS (FIL)                                415,700
NORTHERN TRUST LONDON (FIL)                                    105,300
JP MORGAN, BOURNEMOUTH (FII)                                 1,192,800
TOTAL                                                       67,595,233


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




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 KNOWN



11. Date company informed


12 SEPTEMBER 2005





12. Total holding following this notification


67,595,233



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)


7.01%



14. Any additional information


SHAREHOLDER PREVIOUSLY REPORTED THAT IT HAD A HOLDING OF 65,868,210 SHARES 
(6.83%) IN THE COMPANY ON 28 JUNE 2005.



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


12 SEPTEMBER 2005






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