EXHIBIT 99.1
                                  Certification
           Pursuant to 18 U.S.C. Section 1350, as adopted pursuant to
                  Section 906 of the Sarbanes-Oxley Act of 2002
                (Chapter 63, Title 18 U.S.C. ss.1350(a) and (b))

Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 (Chapter 63, Title 18
U.S.C. ss.1350(a) and (b)), each of the undersigned hereby individually
certifies in his capacity as an officer of Shire Pharmaceuticals Group plc (the
"Company") that the Annual Report of the Company on Form 10-K for the year ended
December 31, 2002 fully complies with the requirements of Section 13(a) of the
Securities Exchange Act of 1934 and that the information contained in such
report fairly presents, in all material respects, the financial condition and
results of operations of the Company.


Dated:  March 28, 2003                          /s/ Matthew Emmens
                                                --------------------------------
                                                Matthew Emmens
                                                Chief Executive


The foregoing certification is being furnished solely pursuant to Section 906 of
the Sarbanes-Oxley Act of 2002 (Chapter 63, Title 18 U.S.C. ss.1350(a) and (b)),
is not a part of the Form 10-K to which it refers and is, to the extent
permitted by law, provided by each of the above signatories to the extent of his
respective knowledge.

A signed original of this written statement required by Section 906 has been
provided to Shire Pharmaceuticals Group plc and will be retained by Shire
Pharmaceuticals Group plc and furnished to the Securities and Exchange
Commission or its staff upon request.