(19)

(11)

EP 0 579 635 A1

(12)

(43) Date of publication: 26.01.1994 Bulletin 1994/04 (21) Application number: 92907473.0 (22) Date of filing: 03.04.1992

(51) International Patent Classification (IPC):  A01N 63/ 00( . ) C12R 1/ 39( . ) C12N 1/ 20( . ) (86) International application number: PCT/GB1992/000597 (87) International publication number: WO 1992/018613 (29.10.1992 Gazette 1992/27)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IT LI LU NL SE (30) Priority: 11.04.1991 GB 19910007678 (71) Applicant: IMPERIAL CHEMICAL INDUSTRIES PLC London SW1P 3JF (GB)	(72) Inventors: RENWICK, Annabel Bracknell Berkshire RG12 4ZG (GB) POWELL, Keith, Adrian Nr Bracknell Berkshire RG12 5ES (GB) CAMPBELL, Richard Bristol BS8 1UG (GB) (74) Representative: Huskisson, Frank Mackie, et al  ICI Group Patents Services Dept. PO Box 6 Shire Park Bessemer Road Welwyn Garden City Herts, AL7 1HD Welwyn Garden City Herts, AL7 1HD (GB)