Re: Holding in Company

Tullow Oil PLC
18 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


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


 5,128,700 since last notification



6. Percentage of issued class


1.36%



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


17 May 2004



12. Total holding following this notification


17,240,100



13. Total percentage holding of issued class following this notification


4.56%



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


18 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