(19)

(11)

EP 0 873 643 A1

(12)

(43) Date of publication: 28.10.1998 Bulletin 1998/44 (21) Application number: 96931176.0 (22) Date of filing: 23.09.1996

(51) International Patent Classification (IPC):  G08B 25/ 10( . ) (86) International application number: PCT/GB1996/002343 (87) International publication number: WO 1997/013230 (10.04.1997 Gazette 1997/16)

(84) Designated Contracting States: AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE (30) Priority: 21.09.1995 GB 19950019261 (71) Applicants: Farragher, Patrick Joseph Oxford, OX2 8HE (GB) Currah, Stephen Thomas Alnwick, Northumberland NE66 3LE (GB)	(72) Inventors: Farragher, Patrick Joseph Oxford, OX2 8HE (GB) Currah, Stephen Thomas Alnwick, Northumberland NE66 3LE (GB) (74) Representative: Everitt, Christopher James Wilders, et al  fJ CLEVELAND 40/43 Chancery Lane London WC2A 1JQ London WC2A 1JQ (GB)