Last week, he explained that he was going to take immediate, decisive action by changing his party rules rather than waiting for the government or parliamentary authorities:
An independent inquiry into MPs’ expenses is underway, but it won’t be reporting until later this year. I don’t want my party to wait that long. So I want to set out this afternoon the action I’m taking right now.
And by that I don’t mean things I’d like the Government to do. I don’t mean things I’d like the House of Commons Committee to look at. I mean things that my Party, the Conservative Party; Conservative MPs, the things that they will do – right now.
This week, he explains that the cash-for-pretty-much-anything scandal can only really be dealt with at the ballot box:
I think there is now only one way of sorting out the mess, and that is for Parliament to be dissolved and for a General Election to be held right away. This political crisis has been caused by the politicians, so I don't think the politicians alone can solve it. The public have got to be involved. Think about the big questions that we as a country need to answer.
How can we make sure, in a fair way, that everyone has the chance to express their views about their MPs' behaviour, except by letting them vote in a General Election?
But why wait for Gordon Brown to call an election? Cameron and his MPs can do something right now to address their side of this problem: they can all do a David Davis.
Now, Davis’s reasons for standing down and seeking re-election last year were pretty incoherent, but this situation actually makes that sort of byelection antic a lot more logical: many MPs have had their integrity called into question by the publication of their expenses antics, and the rest are being tarred with the same brush. Any MP who thinks it’s a good idea in these circumstances to refresh their mandate can do so just like that.
Cameron could take the lead now and urge the rest of his MPs to follow. It’s hardly likely that Brown would call an early election when he’s so far behind in the polls. So quit, Dave, if you really mean it. Quit while you’re ahead.
Like I say: quixotic and mischievous. But not completely. Imagine if the Tories actually did this. Imagine how they could say they had the guts to go directly to the voters without delay while Brown cowered in his Westminster bunker. Imagine the constitutional earthquake of 200-odd MPs suddenly quitting the Commons. I’m not in the business of giving strategic advice to the Tories, but it’s a intriguing thought.