That's weird. I've just found an old 50p coin on the floor of my living room - one of the reasonably-rare 1973 coins with the ring of hands instead of Britannia on the reverse, that look like this. It must have come from the carrier bag of copper coins, miscellaneous old motorbike keys and similarly-sized objects, which has been lying on the floor since I moved in (really need to find a cupboard or maybe a bank to put it in) and has recently been accidentally ripped open by my sofa and spread its contents all over the floor. But I wasn't aware there was a 50p in there. I must have saved it, years ago, when the old-style 50ps were being phased out, but I don't remember doing it.
I like surprises! I must make a point of concealing other little trinkets among my old junk, so my future self can find them! What with the old 10p I got from Roel last month, I'm indulging in pleasant memories of the halcyon days when money was quite a bit bigger than it is now. Ahh, wasn't life great then?