This has been posted far and wide, but it's important so here I am posting it again:
Until recently Tor UK followed the submission policy of Macmillan in that we didn’t accept direct submissions. To be honest, with so many submissions from agents, plus manuscripts from existing authors and actually publishing books – there’s little to no time to actually go through what we used to fondly designate the ‘slush pile’.
Ah, I kid. I kid because I love.
Tor is interested in finished novel-length manuscripts only. They want you to email them science fiction, fantasy and horror novels between 95,000 and 150,000 words. Interestingly, and in a sign of the times, they don't want hard copies, and will trash them unread.
Here is the formatting info: http://torbooks.co.uk/2013/01/29/submitting-a-novel-to-tor-uk/