K.I.S.S.

The best systems are the simple ones. The more complicated they get, the more likely it is they will go wrong. The Tax Credit System is horribly complicated, and I'm not in the slightest surprised that it's in trouble. But even the basic principle is barmy - you pay people money for this year on the basis of what they earned last year. If this year they earn more, that creates an overpayment which you then ask them to repay. But by their very nature, these are mostly people at or near the breadline, who spend money as they get it, so how are they supposed to repay? If there's one thing worse than a complicated system, it's a silly complicated system!