On one level, attempting to ally himself with Churchill is shameless, blatant stuff. But just as when Boris was caught and filmed on a zip-wire in the Olympic Park in 2012, swinging in mid-air waving two small Union flags, he somehow gets away with behaviour which would prove fatal to the prospects of other politicians if they dared try it. This apparent invincibility of brand Boris amuses and infuriates his critics and some of those who have worked with him down the years. Several of them emerged from the experience convinced that Boris would sell his grandmother if he suspected there might be a column or amusing speech in it. The charge is that for all his erudition he lacks seriousness to a dangerous extent. Could he be trusted, they ask, with the nuclear deterrent, or the fragile Union, or negotiations with the President of the United States? And does he have the patience to apply himself to the serious business of government?

The lesson from his time as Mayor of London is that he tends to surround himself with capable people while he gets on with composing optimistic mood music, being Boris and wooing — very successfully — non-Tories. This is a mode of operation reminiscent of Ronald Reagan, although Reagan had an ideological core of steel. Boris in contrast takes an à la carte view of Conservatism. He loves the Heseltine-style grand project as much as the Thatcherite thought of unleashing animal spirits. 

Yet, for all that he is the man to beat, when Boris makes his run doubts about his reliability remain the territory on which the frontrunner could come unstuck in leadership debates or media appearances. If a rival scores a direct hit in a public forum, and the voters and media grow bored with the favourite, as can happen, he could be defeated.

Officially, all this is said to be the last thing on Boris's mind. The mantra from friends is that he is concentrating on becoming an MP by winning the Uxbridge seat in 2015, oh and on being Mayor of London until 2016. This is absolute nonsense, of course. The small team of supporters and advisers gathered around him are not spending their time dreaming of Uxbridge. They are plotting, trying to persuade MPs of his merits and watching for signs of strength or weakness on the part of his likely opponents.

In this regard, Boris has been extremely lucky recently, what with Theresa May's bandwagon coming off the rails. The Home Secretary's leadership prospects went through one of their periodic revivals after she won her war with Michael Gove, then the Education Secretary and now the Chief Whip. That steeliness she displayed in confronting Gove, a friend of the Prime Minister, endears her to many Conservative activists who have been looking for the next Margaret Thatcher for more than 20 years. Efforts have been made by her advisers to soften May's image. She is notoriously uncomfortable with small talk although she is surprisingly good at delivering jokes in after-dinner speeches. It is unclear whether she writes the jokes; it is suspected not. A recent appearance on Desert Island Discs was also meant to help bolster her credentials.

And then, disaster struck in November in the shape of the European Arrest Warrant. The ensuing farce when the government attempted to reintroduce the EAW was not entirely her fault and the whips' office — now run by her old enemy Gove — was blamed for devising a transparently daft procedure that sought to avoid a vote on the warrant itself. Amid chaotic scenes, with furious Tory backbenchers accusing ministers of duplicity, May was at the despatch box. Odds on her being the next Tory leader lengthened that night.