Increases Stake in UK assets

Tullow Oil PLC
04 June 2003

TULLOW OIL INCREASES STAKE IN NORTH SEA HORNE GAS DISCOVERY


Tullow Oil plc ('Tullow'), the independent oil & gas exploration and production
company announces that it has agreed to purchase from BP for the sum of
£2,269,000, plus a contingent payment of £500,000, interests in three North Sea
licences. The licences cover various equity interests in five part blocks in the
Southern Gas Basin, due south of the Thames field production complex in which
Tullow has the largest equity interest.

The interests agreed to be acquired by Tullow from BP are as follows:

Licence P133: Blocks 53/3a and b   22.22%
Licence P786: Blocks 53/3c and d   58.83%
Licence P852: Block 53/4bF1        12.00%


Subject to Department of Trade and Industry approval, Tullow will succeed BP as
Operator for Blocks 53/3c and d.

Two of the blocks, 53/3c (in which Tullow now has an interest of 73.83%) and 53/
4bF1, contain the Horne gas discovery which was made in 1992 by well 53/3c-3. On
a production test the well flowed gas at a maximum rate of 55 million cubic feet
per day from a good quality Rotliegendes sandstone reservoir.

Tullow will seek to undertake an early development of Horne, together with the
nearby Wren gas discovery (located in Block 53/4b) in which Tullow already has a
40% interest.

In addition to the development possibilities, the acreage contains a number of
promising prospects and leads as mapped on the latest 3-D seismic, with
potential for additional reserves from the generally prolific Rotliegendes
reservoir sands. It is anticipated that at least one well will be drilled in
2004 to test the highest ranked prospects.

John Lander, Managing Director of Tullow Oil UK Limited stated: 'The acquisition
of these important and highly prospective interests, close to one of our
producing hubs, fits with our strategy of creating value through targeted
expansion within our core areas. With this transaction, Tullow is well placed to
repeat in the Thames area the success of the CMSIII development.'


For further information contact:

Tullow Oil plc                               Tel: [phone]
Tom Hickey, Finance Director
John Lander, Managing Director, Tullow Oil UK Limited
www.tullowoil.com

Binns & Co PR Ltd                            Tel: [phone]
Emma McCaffrey, Peter Binns, Ben Willey
www.binnspr.co.uk

BP Aberdeen                                  Tel: [phone]
Lynne Staples-Scott



NOTES TO EDITORS

Tullow Oil plc is a UK registered company, quoted on the London and Irish stock
exchanges, and one of the largest Independent Exploration and Production
companies in Europe. Tullow Oil is a dynamic player in the international oil and
gas industry. Its primary offices are in London (UK & Corporate) and Dublin
(International Business).

Tullow Oil has interests in 54 exploration and production licences spread over
three main areas - South Asia, Africa, and Europe. It has regional offices in
South Asia and Europe and is planning to open one in West Africa.




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