Maybe we can use intelligent policy to police immigration.
This is the magic trick that nobody seems to know how to accomplish. I've been watching the whole anti-immigration debates over the election period for a while and I haven't heard any xenophobia relating to it to be honest, other than the media's dishonest spin.
In the case of Nigel Farage, for example, the most anti-immigrant party leader, he repeatedly says that we should judge people on the content of their character, that we should treat people equally, that we should be blind to skin colour. If that's as xenophobic as we get then... I don't think we have much of a problem there!
But yes right now, the immigration is completely uncontrolled chaos. 1 million per year is just unfathomable I could talk about for hours, but I also just don't think we should be sniping all the much needed talent from other countries to keep for ourselves just to prop up our population numbers. Brain drain is a devastating illness in a country and we're contributing to that problem.
The bigger solution, to me, is to make living in the country more conducive to rearing children. This is the same problem everywhere. South Korea being the worst. Why? Because it's too expensive to raise kids. They've poured billions of dollars into desperately convincing people to have more kids but until it's affordable, it ain't gonna happen.
I think we're all learning to become corporate vassal states where everyone is raised to believe that acquiring wealth is everything, at the expense or normal human behaviour like raising a family.
Now, a successfully managed decline of a population is actually a valid outcome. If our population falls at a much slower rate so there's no shock to the economic system, it could actually be the best outcome (since we can't just grow infinitely, either). Just... easier said than done