Holding in Company

Tullow Oil PLC
12 March 2004

                                  SCHEDULE 10

                   NOTIFICATION OF MAJOR INTERESTS IN SHARES



1. Name of company


Tullow Oil plc



2. Name of shareholder having a major interest


FMR Corp and its direct and indirect subsidiaries and Fidelity International Limited (FIL) and its direct and indirect
subsidiaries.



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


Notification relates to above-named shareholders' non-beneficial interests held through direct and indirect
subsidiaries including: Fidelity Management Trust Company (FMTC): Fidelity Investment Services Ltd (FISL) and Fidelity
Pension Management (FPM).



4. Name of the registered holder(s) and, if more than one holder, the number of
shares held by each of them


        18,500    FMTC     State Street Nominees Ltd.

        14,200    FMTC     Brown Brothers Harriman

         9,500    FMTC     State Street Bank & Trust

    17,213,622    FISL        Chase Nominees Ltd

       638,338    FISL        Chase Manhattan Bank London

     2,526,300    FPM        Chase Nominees Ltd

       732,600    FPM        Northern Trust

       514,000    FPM        Citibank

       271,000    FPM        HSBC

       392,900    FPM        Bank of New York London

     7,412,500    FIL           MSS Nominees Ltd

     1,600,797    FIL           Bank of New York - Brussels

     5,040,767    FIL           Chase Nominees Ltd

       220,848    FIL           Bankers Trust

       467,199    FIL           Bank of Ireland

        60,400    FIL           Brown Brothers Harriman Ltd. LUX

     3,312,808    FIL           HSBC Client Holdings Nominee (UK) Limited

     1,254,800    FIL           Chase Manhattan Bank London

     2,101,500    FIL           Northern Trust

       231,400    FIL           State Street Bank & Trust

     2,284,800    FIL           Bank of New York London

     2,866,300    FIL           Nortrust Nominees Ltd

       123,100    FIL           Deutsche Bank

        92,200    FIL           Mellon Nominees Ltd

     1,298,158    FIL           JP Morgan

      729,400     FIL           State Street Nominees Ltd

     1,076,100    FIL           Morgan Stanley

       112,454    FIL           Deutsche Bank AG, London



5. Number of shares / amount of stock acquired






6. Percentage of issued class






7. Number of shares / amount of stock disposed






8. Percentage of issued class






9. Class of security


Ordinary 10p shares



10. Date of transaction






11. Date company informed


11 March 2004



12. Total holding following this notification


52,616,491



13. Total percentage holding of issued class following this notification


13.93%



14. Any additional information


Total shares in issue 377,841,915



15. Name of contact and telephone number for queries


Tom Hickey  0207 333 6800



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


Tom Hickey



Date of notification


12 March 2004



The FSA does not give any express or implied warranty as to the accuracy of this
document or material and does not accept any liability for error or omission.
The FSA is not liable for any damages (including, without limitation, damages
for loss of business or loss of profits) arising in contract, tort or otherwise
from the use of or inability to use this document, or any material contained in
it, or from any action or decision taken as a result of using this document or
any such material.


This announcement has been issued through the Companies Announcement Service of
The Irish Stock Exchange


                      This information is provided by RNS
            The company news service from the London Stock Exchange