Holding(s) in Company

Radstone Technology PLC
21 December 2004

The company has received the following notification:



                                     Wellington Management Company, LLP

                                     57 State Street

                                     Boston

                                     Massachusetts 02109





20 December 2004





Radstone Technology plc

Brian Shears

Company Secretary

Tove Valley Business Park

Towcester

Northants NN12 6PF

UK



Re: Notification concerning interests in shares of Radstone Technology plc (the
"Company")



Dear Mr. Shears:



1.

Wellington Management Company, LLP ("Wellington Management") is registered as an
investment adviser with the United States Securities and Exchange Commission and
acts as discretionary investment manager on behalf of various separate (the "
Accounts") that hold an interest in shares of the Company.  Wellington
Management's interest in the shares is as an investment manager, as is mentioned
in Section 205(5) of the Companies At 1985 (the "Act").  The Accounts do not act
as a group nor do they act in concert with respect to the interests in shares.
Wellington Management acquired the interests in shares for the Accounts in its
capacity as discretionary investment manager to, and solely for the benefit of,
the Accounts, and the interests were acquired solely for investment purposes.
The shares are registered in the name of the Accounts or the Accounts'
custodians or nominees according to their respective holdings.



2.

Wellington Management as discretionary investment manager on behalf of the
Accounts has purchased, in the aggregate, an interest, within the meaning of
Sections 203 and 208 of the Act, in 1,817,800 ordinary shares, or 5.4% of the
shares outstanding of the Company.  This is an increase of .60% since our
notification on November 29, 2004.  Therefore, Wellington Management hereby
gives notice to the Company of such interest in shares, pursuant to the
provisions of Sections 198(1) and 208(4)(B) of the Act.



3.

This notice is given in fulfilment of, and for the express purposes of
discharging the obligations imposed on us by, Sections 198(1) and 208(4)(B) of
the Act and arising out of the circumstances referred to in paragraph 2.



If you have any questions or commitments, please do not hesitate to contact
Christine Chandler at 617-790-7265.



Regards



Andres E. Saldafia

Vice President and Counsel

Wellington Management Company, LLP


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