Why London? Everyone heads there. There is a lot more of England to choose from.
I can't agree with Paulie's post above (although he has a right to his opinion). I think everyone in the world should be free to move where they like. I also think we need more people with the positive attitude to sacrifice everything they have and work hard for a fresh start, not fewer.
Also if you start limiting people coming into a country then you should also stop people leaving. Or is emigration ok?