T owards the end of the 1970s, the brief but spectacular career of those punk rockers and folk devils the Sex Pistols was followed by The Great Rock’n’Roll Swindle, a rather tawdry drama-documentary. It recast their rise and fall as a huge scam, summed up by a slogan on a T-shirt worn by their former manager Malcolm McLaren: “Cash from Chaos”.

Back then, that motto was a neat representation of his personal brand of cultural mischief. But the culture always takes unexpected twists and turns – and 50 years on, an almost-identical maxim seems to be defining the fate of an increasing chunk of the British retail economy.…