This leads to everyone getting poorer, as there are no more immigrants to exploit. People no longer can get their houses renovated on the cheap, municipalities don't have cheap labor to pick up the trash and clean public toilets. Of course, since the immigrants come from even worse conditions, actually being economically exploited in the UK is a great deal for them. A win-win.
I worked as a barman, a shelf stacker, a fruit picker, a stock picker (I mean the guy at the back of the warehouse stacking trolleys with orders) before I transitioned to software.
I was on minimum wage. I wasn't exploited, it was a means to an end.
I don't think you would really care about me as an individual. I think you just didn't want my type here.