I think a harsh post peak scenario you elude to , I think the UK and the EU would not accept even genuine asylum seekers.We recognise these islands are essentially full up except for the most deserving cases seeking asylum from tyrannies. This will not be easy: as Peak starts to bite, the number of tyrannies are likely to increase world wide.
I am not saying it is right , and it is almost unthinkable in todays PC climate.
But as you say, poverty and unemployment throws the rule book out the window. There was a piece by stanton on the ASPO website (which was very controversial and I didnt agree with most of it), but he said political correctness is afforded now by the cushion of cheap energy. Once that cheap energy is gone , so will the political correctness.
Not nice, but probably true.
Mind you , if we think energy will be in such short supply we cannot even keep the lights on , then bugger knows how thousands of refugees are gonna get halfway around the globe!! We cannot have the doom both ways !