With little more than a month before the elections, and with Boris 12% ahead in the polls, the left are finally focusing on how to stop the man so many of them have ruled out.
Early attacks on Boris as a bungling racist toff clearly had little effect. They were a lazy effort which played only to their own side's already held beliefs. Even worse, they were a symptom of their complacency. No incumbent candidate, no matter how underwhelming their opponent, can ever expect an easy ride into a third term. Ken, a battle-scarred politician with a lifetime of enemies, was always going to find it especially tough.
And yet, when the left looked at their opponent, an incompetent bungler, a much-sacked man of letters, they just couldn't work themselves up to be frightened.
How could this clown, how could this disaster-prone buffoon ever be a credible threat to an experienced and wily politician? And how could the public ever be so stupid or so careless, to vote in a man with little previous interest or experience in real politics?
They took comfort too in Livingstone's satisfaction ratings. The majority of the public it seemed, were happy with Ken and London. Why would they be so foolish as to risk it on an established and notorious disaster-zone?
And yet, as the latest opinion polls show, that is exactly what they are prepared to do. Three months of campaigning from the Evening Standard and a tightly controlled and alcohol free Boris have left many with the sentiment of: "Time for a change".
Boris' team have run a deliberately low-key campaign. His appearances have been tightly controlled with interviews limited. His only 'serious' interview with Andrew Marr, was laughable with Boris blustering through a pre-prepared speech. Marr was half-angered and half-amused by his own failed attempts to get a word in edgeways.
Performances since then have been firmly in the hands of Lynton Crosby. Today they announced that Boris would take part in a 'debate' in a 'virtual speakers corner.' This debate consists of Boris making speeches to web camera, and users posting responses below. This is hardly the kind of presidential debate that David Cameron made such a fuss about.
In fact despite Cameron's mocking of Brown, both Livingstone and Paddick have tried and failed to secure a set of television debates with Johnson. And with his position in the polls, why should he risk it?
And yet if the left are to defeat Boris, this is exactly what they must achieve. Boris is safe when reading a speech or making a gag, but he has repeatedly shown a failure to grasp figures and detail. To expose him, Livingstone and Paddick must get him out into the open. This is where he will be on a daily basis if he becomes mayor, so that is where they must drag him now.
Boris past and policies will not keep him out of City Hall. But seeing him scrutinised and flustered just might.