I think I have shared this one before - back in the bad old days CND decided to show how vulnerable the trains carrying nuclear material were by making a mock up of an RPG and standing on a platform on ‘middle of the no-where by sea’ station as one of those trains went by.
Cue much wailing and gnashing of teeth and why ’someone’ didn’t ‘do something.
British Rail then issued a statement that it wasn’t against any rail byelaws to carry a bazooka onto the premises of train station.
Finally section 5(1)(ae) of the Firearms Act 1968 makes sense. General offence should one have in their possession, acquire, or purchase -
any rocket launcher, or any mortar, for projecting a stabilised missile, other than a launcher or mortar designed for line-throwing or pyrotechnic purposes or as signalling apparatus
You can tell it was a railway, BTP are useless. Anyone else would have just locked up someone for Breach of the Peace and "sorted it out back at the nick".
("So Boumer, why was PACE brought in? Funny you ask let me tell you about some people I heard about in the Met")