It's still the UK! XD
I made the British campaign easier on myself and used release puppet wargoals rather than free people one region at a time for Canada, New Zealand, Australia, South Africa, and Ireland.
Also, two really weird things happened in this game:
1) Free Morocco! I had nothing to do with that at all. They're not in any sphere and they don't have any allies, but no one ever tried to invade them.
2) GB took a piece of Portugal. You can still see it there. I thought about making them give it back to make the borders pretty, but I decided against it.
EDIT: Germany, by the way, was pretty weak since they lost their western provinces to France and Belgium and a good chunk of the east to Poland (and of course, Holstein is still in Scandinavian hands). They also pretty much ignored the infamy limits - I have no idea why, the AI is usually allergic to infamy but in this game they started launching wars with no CB left and right. Their infamy is about 80, I think.
((Hooray - my 500th post.))