In accordance with EC Safety Signs Directive 92/58/EEC on the provision and use of Escape Route Signing, Fire Exit Right, (Expanded), conforms to British Standard 5499 and satisfies both the Building Regulations 1991 and the Health and Safety (Safety Signs and Signals Regulations) 1996. BS 5499 requires a green rectangle or square with the pictogram or text in white positioned centrally and symbols that comply with the proposed European
ISO 7010. On a practical level though, any value this piece of signage might have in an emergency is negated by coupling it with the parlour trick of ‘forced perspective’. There is not, however, currently any mention of optical illusions in the current British Standard regulations.