The MPs' expenses scandal is back - but did you hear about the one who paid off a private mortgage while billing the taxpayer for a loan on his second home? The same millionaire MP who claimed close to the maximum on mortgage allowances in recent years? And who says he can't quite remember how many homes he owns?

You probably haven't come across his story - even though his name is David Cameron. The Tory leader has had a good media week. As I write, the BBC News website is leading with: "Pay up or quit, Cameron warns MPs". How about Dave paying back the money he could have saved us all if he had not chosen to pay off a £75,000 mortgage on his £1.5m London home? And this just months after taking out a £350,000, taxpayer-subsidised mortgage on his second home, in Oxfordshire, in 2001.

Cameron's actions did not break any rules, but experts calculate that, had he paid the £75,000 towards his second home, the taxpayer would have saved roughly £22,000.

But Sir Thomas Legg, who is auditing MPs' expenses, seems unconcerned, and the media are not interested, so Dave continues to claim mortgage interest. But he has said that if he becomes PM next year and has use of the official Chequers country residence, he will give up his second-home allowance completely.

I guess that's one reason to vote Tory.