@Scirocco
"Well, if you ask the people already here to do those jobs, they tend to say no. Or do a resoundingly shit job. As a society we do need people to do the jobs, so it's a good thing that people are willing to come and do them."
So right now there are 9 million economically inactive people in the UK. As a radical idea rather than importing labour to do jobs why not get the people who are already in the UK to do the work.
In answer to your statement that "they tend to say no" then you might ask why is this?
The answer is that for private businesses it's more profitable for them to pay low salaries to imported labour than it is to pay higher salaries to existing UK nationals. And for the Government it is cheaper to hire say nursing staff from abroad rather than pay UK nationals the higher salaries that would attract people into say nursing.
It is economically insane to be paying UK nationals benefits to remain economically inactive and at the same time bring in workers from overseas to do the work simply because greedy employers want higher profits or the Government doesn't want to pay the salaries that would recruit and retain.
You may sneer and write off these economically inactive as "doing a resoundingly shit job" but I on the other hand want to bring them back into work by making it more attractive to be employed than not, benefiting them, the economy and society.