“It’s the young people, apparently,” said the elderly man at my elbow, crouched – like I was – on the floor of Waitrose, looking mournfully at the shelf where the whole milk should be. Not for the first time that week it was bare, bar one small, lonely bottle. “They buy it as soon as it comes in. They’ve found out about it on TikTok, that video thing,” he continued. We straightened up – he with an ease that suggested whole milk was not new to his joints – and discussed the merits of this full-fa