Re: Holding in Company

Tullow Oil PLC
01 September 2003

                                  SCHEDULE 10

                   NOTIFICATION OF MAJOR INTERESTS IN SHARES



1. Name of company


Tullow Oil Plc



2. Name of shareholder having a major interest


M&G Investments



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


As Above



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


Chase Nominees - 6,085,923
Clydesdale Nominees - 40,816,686
Other- 5,972,000



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


10p Ordinary Stock



10. Date of transaction



11. Date company informed


28/8/03



12. Total holding following this notification

52,874,609



13. Total percentage holding of issued class following this notification


13.99%



14. Any additional information




15. Name of contact and telephone number for queries


Tom Hickey
Tel: [phone]



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


Tom Hickey



Date of notification


29/8/03









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








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