How many days' notice do I need to give when quitting a contracted position in the UK?

[Here's Kermit]

I am currently a few months into 1-year contract at a job that I really don't like. I have had another very good offer for January which I am going to take. My contract doesn't have a clause stating how much notice I need to give, so I was wondering if there is a standard (legal) notice period? In the states it's two weeks, what about here in the UK?

Any help in appreciated.