Holding(s) in Company

Spirent PLC
28 June 2005

                                  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


JP MORGAN, BOURNEMOUTH (FII)                                      1,192,800
BANK OF NEW YORK BRUSSELS (FIL)                                     415,700
BROWN BROTHERS HARRIMN LTD LUX (FIL)                             25,194,094
NORTHERN TRUST LONDON (FIL)                                         105,300
JP MORGAN BOURNEMOUTH (FISL)                                     22,068,976
BANK OF NEW YORK BRUSSELS (FPM)                                   1,999,100
BANKERS TRUST LONDON (FPM)                                          823,500
CLYDESDALE BANK PLC (FPM)                                           181,200
HSBC BANK PLC (FPM)                                                 317,600
JP MORGAN BOURNEMOUTH (FPM)                                       5,071,331
MELLON BANK (FPM)                                                 1,651,600
MIDLAND SECURITIES SERVICES (FPM)                                   415,500
NORTHERN TRUST LONDON (FPM)                                       3,845,700
STATE STR BK AND TR CO LNDN (FPM)                                 2,541,809
BROWN BROTHERS HARRIMAN AND CO (IN FORM OF 11,000 ADRS) (FMRCO)      44,000

TOTAL                                                            65,868,210


FII = Fidelity Investments International
FIL = Fidelity International Limited
FISL = Fidelity Investment Services Limited
FPM = Fidelity Pension Management
FMRCO = Fidelity Management & Research Company


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

N/A


8. Percentage of issued class


N/A


9. Class of security


ORDINARY SHARES OF 3.3333 PENCE EACH


10. Date of transaction


NOT KNOWN


11. Date company informed


27 JUNE 2005


12. Total holding following this notification


65,868,210


13. Total percentage holding of issued class following this notification


6.83%


14. Any additional information


SHAREHOLDER PREVIOUSLY REPORTED A SHAREHOLDING OF 54,811,296 SHARES (5.69%) 
ON 27 JUNE 2005.


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


28 JUNE 2005


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