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                                                                    Exhibit 31.1

                                 PROTHERICS PLC

                            CERTIFICATION PURSUANT TO
                  SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002

I, Andrew J. Heath, certify that:

         1.       I have reviewed this annual report on Form 20-F of the
registrant, Protherics PLC;

         2.       Based on my knowledge, this annual report does not contain any
untrue statement of a material fact or omit to state a material fact necessary
to make the statements made, in light of the circumstances under which such
statements were made, not misleading with respect to the period covered by this
annual report;

         3.       Based on my knowledge, the financial statements, and other
financial information included in this annual report, fairly present in all
material respects the financial condition, results of operations and cash flows
of the registrant as of, and for, the periods presented in this annual report;

         4.       The registrant's other certifying officer(s) and I are
responsible for establishing and maintaining disclosure controls and procedures
(as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) for the registrant
and have:

                  a)       designed such disclosure controls and procedures, or
         caused such disclosure controls and procedures to be designed under our
         supervision, to ensure that material information relating to the
         registrant, including its consolidated subsidiaries, is made known to
         us by others within those entities, particularly during the period in
         which this annual report is being prepared;

                  b)       evaluated the effectiveness of the registrant's
         disclosure controls and procedures and presented in this annual report
         our conclusions about the effectiveness of the disclosure controls and
         procedures, as of the end of the period covered by this annual report
         based on such evaluation; and

                  c)       disclosed in this annual report any change in the
         registrant's internal control over financial reporting that occurred
         during the registrant's most recent fiscal quarter (the registrant's
         fourth fiscal quarter in the case of an annual report) that has
         materially affected, or is reasonably likely to materially affect, the
         registrant's internal control over financial reporting; and

         5.       The registrant's other certifying officer(s) and I have
disclosed, based on our most recent evaluation of internal control over
financial reporting, to the registrant's auditors and the audit committee of the
registrant's board of directors (or persons performing equivalent functions):

                  a)       all significant deficiencies and material weaknesses
         in the design or operation of internal control over financial reporting
         which are reasonably likely to adversely affect the registrant's
         ability to record, process, summarize and report financial information;
         and

                  b)       any fraud, whether or not material, that involves
         management or other employees who have a significant role in the
         registrant's internal control over financial reporting.

Date: September 30, 2003

                                                   /s/ Andrew J. Heath
                                                   ----------------------------
                                                   Andrew J. Heath
                                                   Chief Executive Officer

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