Q337: Is it illegal to carry a knife around in my pocket?
It is illegal to carry any sharp or bladed instrument in a public place (with the exception of a folding pocket knife, which has a blade that is less than 7.62 cm (3 inches)).
A lock knife is not a folding pocket knife and therefore it is illegal to carry around such a knife regardless of the length of the blade (if you do not have reasonable excuse). A lock knife means a knife which is similar to a folding knife, in that there is a spring holding the blade closed. However, a lock knife has a mechanism which locks the blade in position when fully extended, the blade cannot be closed without that mechanism being released. A lock knife is not an offensive weapon per se (because these knives were made with a specific purpose in mind and not as a weapon). However, possession of a lock knife in a public place without reasonable excuse is an offence.
Possession of a multi-tool incorporating a prohibited blade/pointed article is capable of being an offence under this section even if there are other tools on the instrument which may be of use to a person in a public place (screwdriver, can opener).
The ban is not total, it is for the person in possession of such an instrument to prove on the balance of probabilities that he/she had good reason for its possession. It will have to be genuine, for example, someone back packing across the Lake District may reasonably be expected to have a knife for the preparation of meals. It will be far more difficult to justify on the streets of a city or town, but there will be occasions when someone is genuinely going to a martial arts sport or scout meeting (which is easily checked).
The penalty for committing this offence is a maximum prison sentence of four years.