[rab] If you haven't already disposed of the beastie. Do you wish to kill the thing or catch it alive and release it somewhere other than your kitchen rather than zap the poor wee thing and have it die a lingering death with a broken back or neck? If so, I have used a wonderful device which works rather well. It's a commercial trap, quite cheap, which is formed from a square section of tubing, one end sealed the other with a spring loaded door. It is also bent. Bait (in my case a dob of peanut butter!) down the sealed end. Place on floor/shelf/whatever with door latched open beneath the device. Mouse wanders in and heads for the other end. Weight of mouse combined with gravity causes the 'far end' to rock back to level - it's the bent end which is elevated. Front end then rises - obviously - and allows the door to snap shut. Viola! one contained mouse. All that remains is to release the thing in an enviroment of your choosing.
update on the expedition home - the M5 was hideous, so we thought we'd try a different route, got hideously lost in Gloucestershire and ended up at home about when I thought. but at least I'm here, eating food prepared by someone else and spending good working time playing silly forum-based games. and I can do my laundry, thank you very much. I'm one of a very rare breed of students that know what a washing machine is and how it works.