That's ridiculous. Why should they adapt to such a large degree? Multiculturalism is amazing. Look how well it works in top cities like Toronto and Melbourne?
If it isn't working in London then that is a British problem isn't it?
Increase in crime rates? Sounds like a policing problem.
Social and resource issues? Who is to say those won't be resolved over time? There's always a period where these newcomers need to adjust. Nothing is gained by being impatient.