I agree that non British nationals who commit serious crimes in this country should be deported.
I would say deport them straight after the trial - save the taxpayer the expense of keeping them in jail.
That said, the vast majority of people who come here from other countries come from within the EU and work here legally, just as so many British people work in Europe, the US, Australia etc.
British people need to stop moaning about how everything is someone elses fault and get off their butts and put some work in!
At my work we have intelligent people from all over the world working together to advance human knowledge and understanding. And that is exactly how it should be.