http://www.legislation.gov.uk/uksi/1996/3064/article/1/made

The Criminal Justice Act 1988 (Offensive Weapons) (Exemption) Order 1996

Offensive weapons

King's Printer of Acts of Parliament

2011-07-04

CRIMINAL LAW

This Order, which comes into force on 1st January 1997, exempts from the offence, in section 141A of the Criminal Justice Act 1988, of selling a knife or certain other articles with a blade or point to persons under sixteen, the sale of a folding pocket-knife with a blade of less than 7.62 centimetres (3 inches) and a razor blade permanently enclosed in a cartridge or housing.