In reply to royal:
> ps - wearing socks doesn't work, just means more sweat!
Sorry, totally disagree with that.
Bare feet in shoes tends to give the inside of your shoes a nice (or completely yukky) slimy feel. The slimy shoes are then cold when you put your feet in them at the start of a session.
If you get really, really thin trainer liner socks, and make sure - this is important - that you don't leave them in your rucksack with your shoes, and wash them after every session, yes, they may get sweaty, but your shoes do not stink like a rotting badger that's been buried in a dungheap for a month.
||-)