Mmm not likely to be cheap. Check out BT OpenZone to get an idea of the current market for WiFi in the UK, I think it clocks in at about 23.5p per minute!!!

Although I'm sure there will be cheaper options if you look around, most are tied into this scheme in one way or another. I always use the easyInternet cafe when I'm in London, it's cheap and easy. I don't think they do WiFi access

Cheers

Cris.