In his VF interview, Black described anal inspections with which he was “slightly mystified at the extent of official curiosity about that generally unremitting aperture.”
Lord Black of Crossharbour is fond of using fancy words, and he sometimes becomes obscure in his efforts to avoid brevity. Still, it might explain something about his character if it's true that his anal sphincter is (as the OED's definition of unremitting has it) "never relaxing or slackening; continuing with the same force; incessant." The main purpose of that particular aperture is to remit material to a lower authority at suitable intervals, and if Mr. Black's is unremitting, well, then, he must be full of it.
*Yes, that's a newspaper reporting on a magazine reporting on a newspaper baron. Our news media are as close as anyone to discovering perpetual motion.