Change in Interest

Tullow Oil PLC
10 September 2001


                  Tullow Oil plc ('Tullow' or 'the Company')

                Notification of Change in Substantial Interest

Tullow has been notified by Schroder Investment Management Limited of the
following change in its interest in the Company. It new holds 42,170,253
shares which are in portfolios managed on a discretionary basis for clients
under investment management agreements. The interest represents 11.81% of the
total of 356,801,138 Tullow Shares currently in issue.

Included in this figure are :

(i) 12,668,004 shares registered nor to be registered in the name of a wholly
owned subsidiary company, Schoder Nominees Limited ('Schoder Nominees')

(ii) 17,637,991 shares neither registered or to be registered in the name of
Schoder Nominees. The registration details are shown on the attached Schedule;
and

(iii) 11,864,258 shares held in (a) unit trust(s) operated and managed by
another wholly-owned subsidiary, Schoder Unit Trusts Limited (SUTL) and
registered or to be registered in the name of Chase Nominees.

                                   Schedule

                             10p Ordinary Shares
Registration                                                             Amount
Frank Russell                                                           850,000
Chase Nominees Limited                                               12,575,590
MSS Nominee Limited a/c: 823654                                         904,397
MSS Nominees Limited a/c: 823666                                        352,465
Nortrust Nominees                                                     2,243,991
State Street Nominees Limited a/c: 5H57                                 711,548
                                                                     17,637,991
10 September, 2001