Sketch: Praise for Dave, but Boris steals the show

Boris Johnson stole the show during the London Olympics 2012. This morning, Conservative prime minister David Cameron had to watch the London mayor dangle the stolen goods at the Tory party conference in Birmingham.

Boris, always a popular figure, has climbed to new heights this week. He was greeted off the train yesterday by a throng of chanting supporters and a scrum of journalists, photographers and cameramen. "It's been a bit of a scrum to get here," Boris told an audience in one of the conference centre's vast halls yesterday evening. 'Typhoon' might be a better word. I saw the media typhoon swirl into the conference centre yesterday evening: anyone who gets sucked into it usually comes to a sticky end. Boris, bemused at the eye of the storm, is newsworthy to the media. To the Tories, he is loved.

"I think I deserve some sort of world record as the biggest harvester of undeserved credit," he said, all modesty, at the rally celebrating the year in which he was both re-elected and 'Olympotastic'. Boris didn't get a medal from London 2012, but he was the Olympics' big winner. So whereas in previous years he has found it easy to win the affection of Tory party delegates, this time around he has them head-over-heels.

Cameron was not present at the Boris rally, which was just as well as it would have been a long way beneath his dignity. This was a big scale love-in, in which a relaxed Boris praised a "musically discerning squirrel" for attacking a member of the pop band One Direction and suggested Jeremy Hunt could participate in a political Olympics for "wanging the bell-end".

Politically, its significance was in Boris' decision to come out fighting for the prime minister. Let no one be in any doubt about "my admiration for David Cameron", he stated. Boris reminded delegates he was one of the first people to back Dave for the party leadership. "I rang him up at a stage when the number of Cameroons could be fitted into a telephone box," he said.

The praise kept on coming in this morning's conference speech, a more formal occasion in which the prime minister took his customary seat, second in from the aisle of the eighth row back. Boris was once again fulsome in his appreciation of the prime minister. But the cumulative effect of his jokes seemed to undermine Cameron, all the same. He revealed that he and the PM had danced 'Gangnam Style'. He mocked Cameron for not knowing the translation of 'magna carta'. He quickly snuck in the point that "we're not going to build a third runway" – the chief point of dispute between Downing Street and City Hall – after having omitted it from the No 10-approved version of his speech. And, worst of all, he pointed out today was Dave's birthday. Cameron shook his head, embarrassed. He knows he has only limited control over the man he called a "blond-haired mop" at the weekend.

"If I am a mop, you are a broom!" Boris responded today. "A broom cleaning up the mess left by the Labour government!" This is the sort of fodder the Tory party loves, and loves deeply. They laughed even more when George Osborne was compared to a dustpan, and Michael Gove to a J-cloth. That's probably a first for the education secretary. Yet, as with all Boris-isms, it's strangely apt. Even when getting in a fix about young people who "make films" in Soho – the highlight of the conference speech – he emerges with his popularity enhanced, not diminished. Boris has the extraordinary ability to get out of jail free on virtually every occasion.

As he put it, there is "one cloud on the horizon: the two Eds [he means Balls and Miliband] could get back into power". The uncertain result of the 2015 general election is indeed a cause of concern for Cameron: it would be hard to carry on if Labour win an outright majority. These are the circumstances in which the Tories might reach out to Boris.

And that is why it was interesting to spot the increasing number of bits of Boris' speeches where he presents himself as a leader of the country, not just of London. He wants to move from "an age of austerity to an age of enterprise", for example. Little by little, the mayor of London is slowly becoming more and more serious. This is disguised by his references to "charismatic mega-fauna in the Serengeti" and the "broken-backed diplodocus of a bendy bus", but it is there.

The Boris phenomenon works with voters. This year he demonstrated that once again; and he remains the most senior Conservative elected in his own right to public office. His party, which has always regarded him with admiration, loves him as much for his success as his personality. It is electoral victory which has helped make Boris such a winning personality in Birmingham; David Cameron, clapping slowly from the eighth row, knows he must come up with the goods in 2015 if he is ever to be as adored.