Come on, Ken, tell us who your donors are

With an MP, such a payment would be a matter of public record. But, thanks to an extraordinary loophole in the party funding laws, Mr Livingstone, though far more powerful than most MPs, doesn't have to declare anything directly at all.

Even though Ken is running a totally personal campaign, and barely lets the Labour Party on his leaflets, he does use it as a clearing house for his money. Any donation to the Mayor's reelection simply appears in the public registers under the heading "National Labour Party", along with a mass of others.

You can only guess which of those donors is funding Ken and which is funding some genuinely national Labour cause. And donations under £5,000, like Ronson's, don't have to be declared, even as "National Labour Party", at all.

Thus accountability is blurred, if not defeated; and thus we reach a deeply worrying place. Because if any single office is most vulnerable to influence-peddling, it's the Mayoralty of London.

This is a job with the biggest personal mandate in the UK; a job described by Mr Livingstone as a "personal fiefdom". And the reason why the Mayor attracts the generosity of Britain's open-hearted property developers is that, uniquely, he is a one-man planning committee.

He - and he alone - has the power to veto any scheme deemed "strategic". From next month, he - and he alone - gets a new power to approve such schemes, too, and to overrule the democratic decision-of local boroughs. (If Ken's reelected, watch out for lots of lovely skyscrapers imposed on a suburb near you.)

Unlike a normal planning committee, Mr Livingstone holds no meetings in public, hears from no objectors and publishes no minutes. In 2002, a London Assembly report described his planning decisions as a "secret garden to which neither Assembly members nor the public can have access, but powerful property interests do".

The report found that developers, Ronson included, would come to Mr Livingstone's office and make their pitch. Sometimes, with the developer still in the room, the Mayor would transform himself into a planning meeting and approve the man's scheme. Tony Arbour, the Tory assembly member who wrote the 2002 report, says that things have "barely changed at all" since. Secret payments by developers who benefited from decisions taken in secret - are you starting to get worried?

There is, of course, an answer. Ken should stop exploiting legal loopholes. He should do what Boris Johnson has done, and publicly declare every donation over £1,000 to himself or his campaign, along with all past donations since 2000. That way, if anyone gets (or got) a favour, people like me can make the connection.

Over Lee Jasper, Mr Livingstone has already shown his tolerance of impropriety and his contempt for accountability. If he again refuses to come clean, it's another reason to hose out the stables in May.