I'd purchase one of Gambols traps, they sound amazing, however thankfully I have no mice as they seem to be afraid of the rats
A rope, a sledgehammer, a button attached to a food dispenser. Rats are smart bastards and they'll quickly learn that pressing the button will release food from the dispenser. Until they press it the 5th time. The rope releases the sledgehammer and splat. Sorted. Copyright (c) Gambol 2012
If you want the little rodent eliminated I would recommend using a normal trap and bait it with peanut butter (crunchy works best). Better results than with any other bait that had been suggested to me. In this weather it is probably a field mouse looking for somewhere warm. You can get humane traps where they can get in but not out, you then have the task of taking them somewhere else to release them. Some Not606ers may be interested in taking them off your hands....................<richardgeretoiletrollupthejacksiesmiley>
Congratulations - can you do us all a favour and put a thread up on the Liverpool board please - they won't want to miss the opportunity to have a minutes silence.