UK EXPLORATION UPDATE

Tullow Oil PLC
03 September 2007

News release


UK Exploration Update: Harrison gas discovery

3 September 2007 - Tullow Oil plc (Tullow) announces that the Harrison
exploration well (44/19b-6), operated by ConocoPhillips, has successfully
encountered a 16m gas column in the targeted Lower Ketch formation. The well,
20km to the northeast of the Murdoch platform, has been drilled to a depth of
4,289m and will now be flow tested. All of the drilling was completed ahead of
schedule and under budget. Further details of the result will be issued
following completion of the test.

Commenting today, Aidan Heavey, Chief Executive of Tullow said:

'This is the eighth consecutive discovery that Tullow has made in the CMS Area
since we acquired the UK assets in 2001. Early assessment of the data from the
well shows that it is in line with our pre-drill expectations and that analogous
prospects in this, and adjacent blocks, have been substantially de-risked.'


For further information contact:

Tullow Oil plc                Citigate Dewe Rogerson         Murray Consultants
([phone])            ([phone])             ([phone])
Tom Hickey                    Martin Jackson                 Joe Murray
Angus McCoss                  Kate Delahunty
Chris Perry


Notes to Editors

Tullow is a leading independent oil & gas, exploration and production group,
quoted on the London and Irish Stock Exchanges (symbol: TLW) and is a
constituent of the FTSE 250 Index. The Group has interests in over 120
exploration and production licences across 23 countries and focuses on four core
areas: Europe, Africa, South Asia and South America.

Tullow's European interests are primarily focused on gas in the UK Southern
North Sea where it has significant interests in the Caister-Murdoch System and
the Thames-Hewett areas and operates over 70% of its production.

In Africa, Tullow has exploration and production in Gabon, Cote d'Ivoire, Congo
(Brazzaville), Mauritania and Equatorial Guinea and a large gas field
development and appraisal programme in Namibia. Tullow also has exploration
programmes in Mauritania, Senegal, Cameroon, Uganda, Congo (DRC), Tanzania,
Madagascar, Angola and Ghana.

In South Asia, Tullow has exploration and production in Pakistan and Bangladesh
and high impact exploration activities in India.

In South America Tullow has high impact exploration interests in Trinidad and
Tobago, French Guiana, Suriname and the Falkland Islands.

For further information please refer to our website at www.tullowoil.com

                                      ENDS


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