(19)

(11)

EP 0 846 275 A1

(12)

(43) Date of publication: 10.06.1998 Bulletin 1998/24 (21) Application number: 96928600.0 (22) Date of filing: 27.08.1996

(51) International Patent Classification (IPC):  G01T 1/ 16( . ) G01T 1/ 29( . ) (86) International application number: PCT/GB1996/002114 (87) International publication number: WO 1997/008569 (06.03.1997 Gazette 1997/11)

(84) Designated Contracting States: DE FI FR GB IT NL (30) Priority: 25.08.1995 GB 19950017491 (71) Applicant: BRITISH TECHNOLOGY GROUP LIMITED London EC4M 7SB (GB)	(72) Inventors: DENDY, Philip, Palin Cambridge CB1 4RT (GB) WRAIGHT, Edwin, Philip Cambridge CB1 2HG (GB) BLOOMER, Steven, David Bedford Bedfordshire MK41 7RP (GB) (74) Representative: Cullis, Roger  Patents Department British Technology Group Ltd 10 Fleet Place London EC4M 7SB London EC4M 7SB (GB)