what an interesting and relevant subject. i wonder what prompted you to post it.
unfortunatley the subject is so full of lies and counter lies that getting accurate facts is difficult (go check the stories about the numbers of asylum seekers, failed asylum seekers, individuals living in britain illegally, and the number of foreign nationals in british prisons)
on a distant but related note, why was it that on the recent (ish) cencus putting ENGLISH as your nationality wasnt an option (or even allowed)
Anyway, britain like every other developed country has a duty to help genuine refugees and individuals that are being persecuted in their native countries. At the same time the massive skills shortages and the pensions fiasco can only start to be corrected with immigrants - ie foreign workers that can ply their trade in britain.
I draw the line at letting foreign criminals into britain, and if a foreign national commits SERIOUS crime in britain, there should be no prison or appeals, just expulsion. (oh, im not too happy about health tourists either)