The term "illegal immigrant" should, perhaps, be replaced by "illegal entrant".
It does not matter, really, what they are called, the really important thing is that there are far too many of them, this being due to other EU countries failing to implement EU law because they know that these people are only "passing through" their countries on the way to the UK.
Far too many of them for what? The current 'influx' represents a splash in the ocean of humanity that currently resides in these Isles alone: assuming 750,000 of them (which is wildly over the top) that would represent an increase in population for Britain of 0.001%.
That would have a financial impact, yes, but there's enough to go round. We'd all have to tighten our belts a little, here and there, but why would we do that for 'others', right?
Those other European countries - many of which have as many applicants as us, if not more - in the main, have lower populations and less money than we do. However, the people attempting to travel through them are attracted by our culture, the fact that many of them speak the language of Britain whereas they don't speak French or Italian or Spanish.
They want somewhere they can settle, somewhere they can build a home, somewhere they can call home, and we treat them like a cross between a disreputable uncle, stray cattle and outright thieves.
O.