What is it about Mayor Boris Johnson that has London hanging on his every word? Is it his comical one-liner quotes, his ability to multi-task (case in point, he is standing for MP while still Mayor of London), his very British sense of humour, or perhaps its all of those combined?

Alexander Boris de Pfeffel Johnson has the sort of name which might more readily attach itself to an ageing circus performer. The incongruities of ‘Boris’, as London’s mayor since 2008 is more widely known, do not stop there. He is dishevelled, frequently overweight and most of the routine of the job still seems to take him by surprise, which adds a sense of comical jeopardy to any undertaking.

In over ten years of covering Mr Johnson’s ascent – now to the position of possible contender for the Tory leadership, I have rarely seen him other than dishevelled, often hasty and with his mind on at least three things at once.

Mr Johnson’s appeal however, lies in an ability to do a number of things extremely well that most people would find difficult with the full beam of their attention. Famously, Boris tends to end up doing at least two jobs at once: he edited the Conservative Spectator magazine while MP for the well-heeled seat of Henley in the early 2000s.

In his second term as mayor, since 2012, he has clearly yearned for the chance to succeed David Cameron as Tory Party leader – and finally decided this summer to stand for a seat in parliament, a possible launch pad for a challenge after the 2015 election.

One way or the other, Mr Johnson’s tenure as mayor is coming to an end. If Ken Livingstone, his Labour predecessor, defined the job as ideal for a noisy populist, Mr Johnson has pulled off a harder trick in being a Conservative in London, a historically left-leaning city.

The Resident: As Boris stands for MP, we ask, is Number 10 the next step?As Boris stands for MP, we ask, is Number 10 the next step?

He has argued vigorously for free enterprise, wealth creators and largely allowing property developers a pretty free hand. Yet he is well-regarded across the political spectrum, regularly topping political popularity polls.

Two things are key to this. One is humour, the other is a watchful guile. Representing London comes easily to a man who has always been a natural performer. The rumbling delivery, mock oratical style: ‘My friends’ and occasionally yelps of ‘Ya, ya, ya’, deployed to distract from inconvenient truths.

I remember first witnessing a Johnson speech there in the Freshers’ week when we had all arrived wet behind the ears as school-leavers and simply marvelling that any 19 year old could sound quite so much like Winston Churchill.

What sounded pompous then (and n Old Etonian, Boris knew how to exude grandeur, long before he actually had it), softened into a style both lofty and amusing. That is a psychologically adept combination in England, because it combines the desire for benign authority with an urge not to take officialdom too seriously.

Crucially, Londoners feel they are on a level with ‘BoJo’. True, his actual achievements look rather slighter than the brio with which they have been achieved. He has brought the ‘Boris bikes’ to London, enshrining its status as one of the world’s must dicey cycling cities. An eye for quirky detail prompted him to relaunch the old, clunky but iconic Routemaster buses with a sleek design by Thomas Heatherwick.

There is also a tougher side to the Mayor: he has extended the running hours of the Tube – popular with all-night Londoners, but roused the ire of the hard-line Tube union by breaking a pledge not to close ticketing offices.

Despite a reputation as a bon viveur (one of the few politicians happy to be seen with a glass of wine at lunchtime), he banned alcohol on Tube trains. But his greatest gift is the ability to use verbal dexterity to get out of hot water.

The Resident: London’s transport systems have been a big focus for Boris JohnsonLondon’s transport systems have been a big focus for Boris Johnson

Revelations of past womanising have not dented his career, unlike others caught out in similar situations. Charles Moore, his old newspaper editor, once reassured Boris that he did not care about his tangled private life. ‘Neither do I,’ responded his protégé cheerfully. These days, with his fiftieth birthday behind him, the loyalty of a sensible barrister wife is an asset Mr Johnson would be unwise to squander.

This sort of levity hides a steely desire for self-advancement. For all his apparent spontaneity, he calculates precisely the moment of political risk. The main hurdle to Mr Johnson’s advance is that he is a similar age to Mr Cameron (they were contemporaries at Oxford), which means that he needs to seize the leadership crown next time around. Now parliamentarians will need convincing, as one puts it ‘that this is more than just a middle episode of the long-running BoJo show’.

The accusation that his first stint as an MP lacked seriousness worried him, so the ‘new’ Boris is attempting to show seriousness and appeal to the harder right-wing Tory vote on tough subjects such as Islamic fanaticism.

But as mayor, Mr Johnson has been keen to celebrate the diversity of London. Any advance on the Tory leadership however is bound to raise the question of his liberal views on immigration. On this issue, Conservatives fear losing ground to another unpredictable populist force: the UK Independence Party. How Mr Johnson will bear up to this tension is one of the singularly most intriguing questions in British politics.

The business community has undoubtedly enjoyed having Boris as a London figurehead a man who is not shy about wealth and once described his own income from writing newspaper columns, nearing £300,000 annually, as ‘chicken feed’. The super-rich, he says, ‘deserve humble and hearty thanks. It is through their sheer wealth-creating dynamism that we pay for an ever-growing proportion of public services.’

The Resident: The business community has undoubtedly enjoyed having Boris as a London figureheadThe business community has undoubtedly enjoyed having Boris as a London figurehead

The biggest uncertainty in this entertaining road-show of wit, nerve and instinct is how Brand Boris will play outside the capital. A dynamic, shifting, tolerant London that has become Boris’s political pulpit is increasingly, a city state unto itself but a national leader needs to reach out and resonate far beyond it.

Few who have known Boris on the rollicking journey of his career would doubt that he intends, as he would put it to ‘have a crack at it’. Asked whether he could be an MP while remaining mayor, he merely says ‘it had been done before’ (for a year, when his predecessor held both jobs). Mr Johnson will not rest until he has the chance to seize the top job. His sister once remarked that her brother’s childhood ambition was to be the ‘world King’. You would not put it past Boris.

Words: Anne McElvoy