If there is one great thing about being a middle-aged man, coming in to work every day, rain or shine, it is this: you don’t ever have to worry about how to dress. It’s a no-brainer. A well-cut suit, plain shirt, subtly patterned tie and formal, polished shoes. That’s it. There are small variations to consider, boldness of tie pattern, width of shirt collar, sobriety of sock. Hefty magazines are devoted to these infinitesimal themes, contradictory arguments shooting back and forth with the fervour of a medieval theological debate. But the commandments are pretty much set in stone. It’s hard to go wrong.

Come the weekend, however, and the headaches begin. The scariest phrase in the English language, if you are a middle-aged man, appears on well-intentioned invitations: SMART CASUAL. That’s just like life, waiting until you are sliding into downtime before it tosses an oxymoron into your sleepy brain.

By far the trickiest part of weekend dressing is footwear. Look: there is no smart casual in footwear. Smart is what you wear to work. Casual is trainers: comfortable, fashionable. A chairman of the Royal Opera House once declared that he never wanted to sit next to anyone wearing trainers. He was ridiculed. It was a seminal cultural-podiatric moment. We are the generation that invented trainers, and now we had earned the right to wear them, whenever, wherever.