Gordon's in trouble - but can Ken save him?

I cannot find a single person in the Labour hierarchy who will say with certainty, "Ken is going to win". The best offer is "Voters are coming back to us - it's just a question of whether it happens quickly enough", which is a long way from bankable.

Over at Camp Boris, the mood is brighter, if nervy, as befits a spirited yearling's trainers: "We can't afford any mistakes," says one.

Mr Johnson has learned fast on this campaign but his case tends to stutter after a prolonged period of exposure. It gave him his worst TV outing on Newsnight last week. It also means that he still needs to "seal the deal" to stop potential voters wavering back to the devil they know.

The main weakness of Mr Livingstone's third-term bid is that the old saw of "Ken just being Ken" looks less appealing when subjected to the close scrutiny of the hardest-fought election since the Mayoralty began.

Boris is likeable. Ken - by the admission of his campaign manager, Tessa Jowell, is "not liked by everyone" (you can say that again). Her defence that amiability is not "essential" rings hollow. Mayors are part of the public face of a city. A bit of likeability doesn't go amiss.

The tensions for New Labour in credibly endorsing Mr Livingstone are palpable. A flawlessly centrist figure drafted in to make Ken attractive to middleclass Londoners, Ms Jowell found herself bogged down in awkward questions at the Evening Standard's debate on Monday about Ken's embrace of the extremist Muslim preacher Al Qaradawi, and his decision to address an organisation with close links to the Tamil Tigers at the Zoroastrian Centre in Rayners Lane.

Well, there's a Monty Python element to enjoy here. Alas, the attentions of the anti-terror squad to the organisation make it rather less amusing.

Of course, Mr Livingstone was not playing footsie with the Tamil Tigers for fun. A vote is a vote. If his old "rainbow coalition" of Left-liberal London, a higher proportion of women voters than his rival and a preponderance of ethnic support shines through the thunder of the campaign, Ken can still recapture the castle.

More than ever now, a Labour Party tethered to Gordon Brown is holding onto that prospect of a London victory to lift its spirits: one drowning man clutching another.

Mr Livingstone and Mr Brown come from different parts of the radical Labour tradition: Ken the maverick master of interest groups, Gordon the stolid poverty crusader itching to control the machinery of state.

Both have been round the block for a while and both face a generational insurgency from their main opponents. "If the message next week is that tough, flawed old Ken can still beat feisty Boris," says one minister, "That would be very welcome omen for the other tough, flawed figure, Gordon Brown, facing his young pretender."

Mr Livingstone doesn't hide the fact that he is shopsoiled. "I'm not horrible," he told me in a rare moment of spontaneity. "I'm just power-hungry." That's Ken at his disarming best: at once frank, manipulative and utterly distinctive.

Labour fears that his power-hunger may no longer be persuasive enough. He has not been put ahead by any of the major polling organisations since Mori in February, so any swing back to him had better happen quickly now.

What really worries Mr Brown and Co is that a collapse in London, combined with a domino effect of councils in marginal seats, would be seen as harbingers of failure nationwide. "There is a huge historical irony lurking here," says one long-standing architect of New Labour's strategy. "Ken was always a sideshow. But after all the drama of Gordon's accession and the change from Blair, it could all simply come down to how he does in London."

Nationally, the mood is grim for the Government. Mr Brown, as one of his aides admits, is "spreading himself thin" in the run-up to the local elections next Thursday. He will make only one more appearance with Ken before the vote, being preoccupied with the need to stamp out rebellion among generally reliable MPs on his abolition of the 10p tax band. This is not just a crisis in Labour, it is a crisis within Brownism, too - and the first time we have seen it so openly and destructively displayed.

It cuts both ways, though. An escape for Ken next week would force David Cameron back to the drawing board on tactics. London has been a golden prize for the revived Tories. Their national polling (see Guardian/ICM this week) is still not stratospheric, despite the Government's woes. They badly need to bring this trophy home to set a course for No 10.

Mr Johnson's energetic campaign has, to his credit, brought them very close to the prize. I must take issue with my esteemed colleague Andrew Gilligan's contention that it does not matter if the candidate had, in a previous job, shown himself to be "crap at the general day-to-day stuff [like] checking the expenses - but great at the strategic vision".

The point about the Mayoralty is not just about vision but delivering on that vision. Making sure things are done on time and costed properly is part of the job. It is a state of mind which applies in large things as well as small. Just as Ken has rightly, if belatedly, been held to account for his lapses here, so we should expect Boris to be - which means he should be on top of the general day-to-day stuff.

It thus remains a weakness that even Mr Johnson's supporters are desperate to discover who is actually going to run the place if he wins the race.

He can take comfort in the knowledge that the Ken campaign has failed in one important point. It has not really made its main charge stick - that Boris is a dangerous liability to the capital city. We may view with some suspended disbelief the prospect that Boris will exhibit all the orderly virtues of public life. But the "Disaster Candidate" tag has not found much of an echo.

There is Labour's wider agony in a nutshell. What is the Gordon national message but "Don't risk it all in hard times by trusting the Tories"? If London does embark on the magical mystery tour of a new Mayor, it will have sent a message that the risk of change is sometimes worth taking. In that case, the writing on the wall for Gordon will be very large indeed.