Holding(s) in Company

Spirent PLC
29 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)                                    8,348,414
STATE STR BK AND TR CO LNDN (FPM)                              6,940,209
NORTHERN TRUST LONDON (FPM)                                    6,389,700
HSBC BANK PLC (FPM)                                            1,676,200
MELLON BANK (FPM)                                              1,651,600
BANK OF NEW YORK BRUSSELS (FPM)                                1,621,800
BANKERS TRUST LONDON (FPM)                                       823,500
MIDLAND SECURITIES SERVICES (FPM)                                415,500
CLYDESDALE BANK PLC (FPM)                                        130,700
JP MORGAN BOURNEMOUTH (FISL)                                  23,968,276
BROWN BROS HARRIMN LTD LUX (FIL)                              23,970,494
JP MORGAN, BOURNEMOUTH (FIL)                                     665,200
BANK OF NEW YORK BRUSSELS (FIL)                                  415,700
NORTHERN TRUST LONDON (FIL)                                      105,300
JP MORGAN, BOURNEMOUTH (FII)                                   1,192,800
TOTAL                                                         78,315,393


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


28 SEPTEMBER 2005





12. Total holding following this notification


78,315,393



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)


8.11%



14. Any additional information


ON 28 SEPTEMBER 2005 THE SHAREHOLDER REPORTED TO THE COMPANY THAT IT HAD 
REDUCED ITS HOLDING IN THE COMPANY FROM 77,397,971 SHARES (8.02%) TO A HOLDING 
OF 76,839,571 SHARES (7.96%).  THE SHAREHOLDER THEN LATER ON 28 SEPTEMBER 2005
REPORTED TO THE COMPANY THAT IT HAD INCREASED ITS HOLDING TO 78,315,393 
SHARES (8.11%) AS SHOWN ABOVE.



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


29 SEPTEMBER 2005






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