Where are the biggest problem debts in the UK?

There was a time when we all talked about credit: the great purchases on our credit cards, the holiday we'd pay for next year, the brilliant 0% deal we'd managed to snaffle. But the credit crunch took the wind out of our sails and now we are far more likely to be talking about debt. The debt that is soaking up our income in interest payments, the debts we can't imagine ever paying off, and the debt that's keeping us awake at night. Of course credit and debt are the same thing - but they certainly don't feel that way.

Problem debts are building up all over the UK, but where is the problem worst, and what can we do about it?