Last week, I played tennis at my club in London. In the court next to me was a man whose business collapsed not long ago, after it had borrowed billions of pounds. He was laughing and seemed relaxed. Somehow I doubt he had given any personal guarantees to the banks.

Following his example, whenever I give advice to would-be entrepreneurs I tell them the single most important thing to remember is never, ever to give any lender a personal guarantee. Do not put your house on the line: there is always another way to find the money. But it seems quite a few borrowers forgot the vital rule.