Thanks all
Why did the caller show his hand first ?
He called very slowly and with the immortal words... "I think I'm beaten, but I have two pair.." at which point the raiser pushed his cards away saying "good call"
When a bet is called, the player who made the last raise should be the one to show his hand as the caller has called to "see" his hand.
As for players not involved at the river asking to see a hand, this is a matter of etiquette, and is considered by many to be "bad form", although imho the called raiser should automatically table his hand.
I don't generally like to do 'bad form' stuff, but I think this was worth making an exception. The cards weren't in the muck, they were clearly distinct on his side of the pot, whilst the muck was the other side of a mountain of chips.
I take kinboshi's point about not rubbing his face in it, but the betting on this hand was strong all through and I wanted to know what he had been betting with and would have forgotten the issue had he not told me in no uncertain terms that it was nothing to do with me because I had folded.
I'll make peace for the argument when I see him next, but also make the point that it is up to him to show when he has been called. This is a small, generally friendly, game; played within everyone's financial comfort zone but 'rules is rules'