Re: Holding in Company

Tullow Oil PLC
19 May 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). The notifiable interests also comprise the notifiable interest  of Edward C. Johnson 3d, a
principal shareholder of FMR Corp. and Fidelity International  Limited



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


        16,200    FMTC     State Street Nominees Ltd.

        14,200    FMTC     Brown Brothers Harriman

          9,500    FMTC     State Street Bank & Trust

 13,819,727   FISL        Chase Nominees Ltd

      499,016    FISL        Chase Manhattan Bank London

      514,000    FPM        Citibank

      271,000    FPM        HSBC

      392,900    FPM        Bank of New York London

   3,302,516   FIL           MSS Nominees Ltd

   1,312,897   FIL           Bank of New York - Brussels

   1,031,382   FIL           Chase Nominees Ltd

      220,848    FIL           Bankers Trust

      467,199    FIL           Bank of Ireland

        70,692    FIL           HSBC Client Holdings Nominee (UK) Limited

      632,300    FIL           Chase Manhattan Bank London

   1,259,300   FIL           Northern Trust

      124,000    FIL          State Street Bank & Trust

   1,668,000   FIL           Bank of New York London

   1,722,500   FIL           Nortrust Nominees Ltd

      134,900    FIL           Deutche Bank

      264,700    FIL           Mellon Nominees Ltd

   1,298,158   FIL           JP Morgan

      729,400    FIL           State Street Nominees Ltd

      868,400    FIL           Morgan Stanley



5. Number of shares / amount of stock acquired






6. Percentage of issued class






7. Number of shares / amount of stock disposed


5,171,908 since last notification



8. Percentage of issued class


1.37%



9. Class of security


Ordinary 10p shares



10. Date of transaction






11. Date company informed


18 May 2004



12. Total holding following this notification


30,643,735



13. Total percentage holding of issued class following this notification


8.11%



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


19 May 2004



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