Holding(s) in Company

Spirent PLC
12 December 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)                                            9,686,114
STATE STR BK AND TR CO LNDN (FPM)                                      8,529,809
NORTHERN TRUST LONDON (FPM)                                            8,123,100
BANK OF NEW YORK BRUSSELS (FPM)                                        1,682,600
HSBC BANK PLC (FPM)                                                    1,675,400
MELLON BANK (FPM)                                                      1,663,300
BANKERS TRUST LONDON (FPM)                                               823,500
MIDLAND SECURITIES SERVICES (FPM)                                        371,200
CLYDESDALE BANK PLC (FPM)                                                118,700
JP MORGAN BOURNEMOUTH (FISL)                                          28,578,587
BROWN BROS HARRIMN LTD LUX (FIL)                                      33,975,986
BANK OF NEW YORK BRUSSELS (FIL)                                          415,700
NORTHERN TRUST LONDON (FIL)                                              136,100
JP MORGAN, BOURNEMOUTH (FII)                                           1,395,500
BNP PARIBAS, PARIS (FIGEST)                                              310,200
TOTAL                                                                 97,485,796


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


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


09 DECEMBER 2005





12. Total holding following this notification


97,485,796



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)


10.09%



14. Any additional information


ON 11 NOVEMBER 2005 THE SHAREHOLDER REPORTED TO THE COMPANY THAT IT HAD
INCREASED ITS HOLDING IN THE COMPANY TO 87,869,003 SHARES (9.10%).



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 - ASSISTANT COMPANY SECRETARY



Date of notification


12 DECEMBER 2005



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