Following an earlier vote by British legislators to allow same-sex marriage, the plans cleared both houses of Parliament this week. USA Today:
Now, all the bill needs is official assent from Queen Elizabeth II, which is expected to come later in the week.
Like the Queen would say no, even if she may! It'll be next year before marriages start taking place, though, due to legal formalities. (Update: Scotland's version of the bill is expected to pass there presently)