He'll be arrested for bail, no matter what, probably charged, probably sentenced (I think they'll probably go for the maximum which is, what? A year in "real" prison?).
I wonder if his lawyer will argue that his time in the embassy should be considered as "on remand", and therefore his client should walk free immediately? The thought amuses me, anyway.
But I can think of people who need to be inside our prisons far more than Assange, and at what, £35k per prisoner per year, I'm not too keen on paying for him to spend another year indoors.