I think if its a locking blade knife over 3 inches total, it isn't permitted, somebody asked cops about carrying the Rescue version whilst at work and they said you could go to court and defend having it but you weren't guaranteed to win as other "non lethal" rescue tools are available (which most UK cops carry, to stay within the regulations)
Sort of!
It is an offence to carry a knife in a public place without good reason unless it is a “readily folding” knife that has a blade with a cutting edge less than 3 inches.
So, if you have good reason to carry a rescue knife, you have good reason. The fact that other rescue tools are available is an irrelevance. The law makes no reference to the availability of other tools, only that you need “good reason” to carry a knife.
Yes, ultimately you might have to argue that in court, though to get there the Police would have to decide to proceed, the CPS would need to agree (and also consider that a prosecution would succeed) and everybody would have to get the paperwork correct!
If you wished to avoid any argument, then the knife must be “readily folding” AND have a blade with a cutting edge less than 3 inches.
I don’t believe the original act intended to prohibit the carriage of lock knives without good reason, but there was one case that went to the court of appeal, and it was decided that if you have to push a button to fold a blade, it is not “readily folding”, so there you go!
Police officers have no exemption from the act, however police officers have been expected, since Victorian times, to carry a pocket knife when on duty, so the “good reason” defence would undoubtedly apply!
Apologies for a lengthy post, especially to our American cousins, but it’s well to be correct!