Re: Holding in Company

Tullow Oil PLC
23 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


Wellington Management Company, LLP



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


Notifiable Interest of Wellington Management Company, LLP



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


Not Stated



5. Number of shares / amount of stock acquired


Not stated



6. Percentage of issued class


Not Stated



7. Number of shares / amount of stock disposed


n/a



8. Percentage of issued class


n/a



9. Class of security


Ordinary 10p shares



10. Date of transaction


Not known





11. Date company informed


22 March 2004



12. Total holding following this notification
12,111,400



13. Total percentage holding of issued class following this notification


3.21%



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


23 March 2004











This announcement has been issued through the Companies Announcement Service of

                           the Irish Stock Exchange.








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