Affiliation: | Current affiliations: Wolfson Unit for Endoscopy (A.V.H., P.Y., B.P.S., S.T.-G.), St. Mark's Hospital, Imperial College London, London, UK, Department of Biosurgery and Surgical Technology (P.T.), Imperial College London, London, UK, Statsconsultancy Ltd (P.B.), Ruislip, Middlesex, UK |