IF UKIP WERE IN POWER, we'd have ALOT less immigration, all control of laws would be sent back to Westminister, and they might actually have something other than gay marriage to talk about, cuts to the military and police would be decreased and we'd have a leader who doesn't talk through his arse! 
Are you sure you didn't participate as an actor in 'This is England'? :roll:
Unfortunately for you, your theory is false. There are, unofficially, "white" and "black" jobs. Some jobs are too humiliating or "useless", that native Brits (whatever that are) won't take them. Jobs like this are usually taken by the ones who doesn't have any other choice. We see the same situation in Norway; where most kiosk workers carries Asian/Middle-Eastern background. The owners of the kiosks are usually native Norwegians.
I went to South Africa this winter. I was expecting the Apartheid-system to be gone. It is. Officially. Unofficially? No. There are no white road workers, not a single white shop assistant, not a single white construction worker. And on the other side, there were none or very few black CEOs, there were none or very few black shop keepers. All the construction leaders were white.
I saw beaches where we expect the "No blacks allowed" signs to be gone. They were, though, there were no natives there. The unofficial apartheid is still there.
Though, this is the kind of society you want. Where native Brits are superior towards the moving immigrants. Being an immigrant is not a fortunate situation. They are not happy. All they want is a democracy and a free world to live in. People like
you, who don't include them in the daily life of a Brit, are the ones who give them the negative view that they have.
And to be very historical; if you British didn't colonize so much, you wouldn't be in this situation anyway.