Going overdrawn can be an expensive business. In the UK, unauthorised overdrafts averaged £680m on any given day in 2006 – just over £10 per bank account. According to the Office of Fair Trading, the charges levied by banks on those overdrafts were £1.5bn, a tasty return of more than 220 per cent. Banks also make money by paying risible interest on positive balances – an incentive to keep your current account lean and, Doh!, to overdraw accidentally – and by other obscure charges. The Office of Fair Trading doesn’t like it and nor do many customers – although they rarely express their displeasure by switching bank accounts.

There are two common responses. People either grumble about money-grabbing banks or point out, smugly, that if only others would manage their affairs responsibly, they wouldn’t incur any of these charges.