The discussion about whether or not to allow people to stay, together with decisions on whether to let people into the UK in the first place are one thing. Consider passengers intending to without entering the UK transit through within eight hours, from one flight to the other, at airports which close and are cleared for several hours during each and every night. They are instead forced to formally enter the UK, each and every one of them, and the whole thing shows how absurd the system is. Unlike in all but smaller regional airports elsewhere, every major airport in the UK closes like this - although I have been told that one of the Heathrow terminals may be an exception.