Holding(s) in Company

Spirent PLC
21 March 2006

                   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


NORTHERN TRUST LONDON (FPM)                                            1,066,700
JP MORGAN BOURNEMOUTH (FPM)                                              627,700
MELLON BANK (FPM)                                                        578,900
BANK OF NEW YORK BRUSSELS (FPM)                                          480,600
STATE STR BK AND TR CO LNDN (FPM)                                        411,800
BANKERS TRUST LONDON (FPM)                                               321,200
MIDLAND SECURITIES SERVICES (FPM)                                        144,700
CLYDESDALE BANK PLC (FPM)                                                 46,300
JP MORGAN BOURNEMOUTH (FISL)                                          39,166,375
BROWN BROS HARRIMN LTD LUX (FIL)                                       9,631,529
JP MORGAN BOURNEMOUTH (FIL)                                              990,000
BANK OF NEW YORK BRUSSELS (FIL)                                          162,200
JP MORGAN, BOURNEMOUTH (FII)                                           2,419,800
BNP PARIBAS, PARIS (FIGEST)                                            2,021,500
TOTAL                                                                 58,069,304


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



5. Number of shares / amount of stock acquired


-



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


-



7. Number of shares / amount of stock disposed


NOT KNOWN



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


NOT KNOWN



9. Class of security


ORDINARY SHARES OF 3.3333 PENCE EACH



10. Date of transaction


NOT KNOWN



11. Date company informed


21 MARCH 2006





12. Total holding following this notification


58,069,304



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)


5.99%



14. Any additional information


ON 17 MARCH 2006 THE SHAREHOLDER REPORTED TO THE COMPANY THAT IT HAD REDUCED ITS
HOLDING IN THE COMPANY TO 63,133,404 SHARES (6.51%).



15. Name of contact and telephone number for queries


MICHAEL ANSCOMBE - 01293 767672



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


MICHAEL ANSCOMBE - DEPUTY COMPANY SECRETARY



Date of notification


21 MARCH 2006






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