after a quick research, i think it's the socket not the plug, it's easier to touch the live wire if the socket is flat.
edit: can't reply to the child comments, maybe there's a time limit, i'll answer here. i have no experience with the british plugs, if you say it's impossible i believe you. i don't understand, though, how does this happen to the person from the top message.
There's a long earth pin on the top of British plugs, the socket doesn't open the holes to allow the other two pins in until that's already inserted to the appropriate depth. So you can't stick anything in to the socket and touch a live wire.
You absolutely can. I've personally be accidentally shocked twice by pulling a firmly inserted plug out of a socket, but it was my own fault. Get the plug partly pulled out then readjust your hand to get more grip around the side of the plug and in doing so accidentally touch the non-insulated section of the live prong just as it is in contact with the live terminal
If both the plug and socket are correctly made, it's physically impossible - by the time the contacts on the plug are exposed, they've disconnected from the contacts in the socket. No matter how much you prod and poke, you should only ever come into contact with an insulated sleeve or a non-energised contact. Unfortunately there are a lot of non-compliant plugs being sold by disreputable online retailers.
It is possible to get a very mild shock from the plug contacts if the input capacitors of the appliance haven't fully discharged. This shouldn't happen with properly-designed appliances, but it's very unlikely to be dangerous if it does happen.
edit: can't reply to the child comments, maybe there's a time limit, i'll answer here. i have no experience with the british plugs, if you say it's impossible i believe you. i don't understand, though, how does this happen to the person from the top message.