Sketch: He praised PMs past and present, but it was all about Boris's future

Boris Johnson arrives to speak at the Conservative party conference in Birmingham yesterday (Getty Images)

It's a tribute to Boris Johnson's rapturously received speech yesterday that, almost unnoticed, he secured a warm round of applause for Sir John Major. Certainly the last Tory PM retains a place in the public's affections, but now the premiership of the whipping boy of the Tory Eurosceptic bastards has been fully rehabilitated even in the eyes of a still Thatcherite-leaning party conference.

Whether that matters to Major is a matter of conjecture. These days, he may sympathise with his Tory predecessor Arthur Balfour, who said he would rather consult his valet than the Conservative conference.

What is clear is that only Boris could have pulled it off, as he did yesterday when, at the climax of his encomium to those who helped put on the Olympics (including Ken Livingstone – "I don't think Ken is going to come back from that one. He just got a clap from the Tory party conference"), he declared: "There is one Conservative we need to thank….Oh, yes. It is thanks to John Major, who put in the lottery, that we have gone from one gold medal in 1996 to the sporting superpower we are today."

But what did this mean? By referring to Major as "one prime minister who loves sport", could Boris have been casting doubt on the enthusiasm of David Cameron? Or was it, more likely, that the sub-text was a veiled reminder that Major was the last Conservative leader to win an outright majority?

It scarcely mattered. Because the tousle-haired party idol trod the high wire between disloyalty and self-promotional cheek with dizzying aplomb from the moment he shambled on to the stage. Like an MC at the old Victorian Gaiety Theatre, MP Gavin Barwell introduced him by commanding the audience to "please welcome the one and only Mayor of London, Mr Boris Johnson." They stood and applauded before he even started speaking, including, gamely enough, Cameron himself, who had been somewhat less tumultuously received as he slipped into his seat in row eight.

But this was, despite the stream of jokes, more than mere music hall. Boris shares with Bill Clinton – a greatly different politician in most, though not quite all, respects – an ability to fold statistics (54,000 houses built, 10,000 new trees, even the Jubilee line running "3mph faster than when I was elected" ) into a rhetorical whole, the implicit argument of which was that if his party can emulate his success in London, nothing can stop them in 2015.

For all his professions of loyalty, it's the speech's little asides that show that his ability to destabilise, however checked yesterday, remains intact: the repeated addressing of Cameron as "Dave" (not even the most demotic of Labourites called Blair "Tone"); the crack about his forgetting what Magna Carta meant; even the wryly muttered praise for Cameron's decision to come to hear his speech. Reverence for the great office of Prime Minister is not a Boris priority. Unless, and until, he gets to No 10 himself of course.

In his own words: the Mayor of London on…

The London 2012 Games "There we were, little old us, the country that made such a Horlicks of the Millennium Dome celebrations in 2000, putting on a flawless performance of the most logistically difficult thing you can ask a country to do in peacetime."

David Cameron "I was pleased to see you called me a blond-haired mop in the papers. If I am a mop, David Cameron, you are a broom – a broom that is clearing up the mess left by the Labour government. And a fantastic job you are doing."