All eyes on Boris as he calculates his future

Boris Johnson is being watched, and it makes him uncomfortable. This is not because the most exuberant showman in contemporary British politics has turned shy suddenly. He does not mind people who recognise him in the street. It is not human eyes that bother him, but the electronic ones.

"When I step out of my front door and I run up Holloway Road, as I do virtually every day, very slowly, I run past more CCTV cameras than along any other stretch of road of comparable length in Europe. My run is photographed in glorious technicolour by, I think, 33 cameras over a very, very short distance. We are the most surveiled society in the world."

This puts the Mayor of London in a dilemma. The libertarian in him would rip down those surveillance cameras but the politician warns him to take care.

We were talking at Cheltenham Racecourse, where the Conservatives held their spring conference yesterday. Johnson had just wowed a fringe meeting with a witty speech and was due to give another at a private dinner for the party faithful. He had not prepared his second speech, yet you just know that he will have wowed them all over again.

His election to the mayoralty a year ago, almost to the day, gave the Conservatives their biggest success at the polls since 1992. One of his proudest boasts from his year in office is that he reduced hooliganism on public transport by imposing a ban on alcohol. But how do you enforce such a ban, and generally make sure passengers behave? One deterrent is a CCTV camera.

Johnson has also agonised over Skype, which allows people to make telephone calls through the internet. The police have the power to demand access to mobile telephone records – too much access, some think – and want the same power to trace Skype calls. As the chairman of the Metropolitan Police authority, Johnson has come down reluctantly on their side.

"People like me who are basically libertarians have such problems with this," he confessed. "In a great many prosecutions the use of mobile phone data has been absolutely indispensable. It has been used to pinpoint murderers. Skype is less easy to track, unless you have a vast data bank. Do we give the police the vast data bank or not? If we don't, murderers will walk free and crimes will not be solved. After hearing all the arguments, I think I am now in favour of giving them access."

As to those cameras, the Johnson solution is fine in principle, but short on details about how it might be put into effect. He explained: "We won't sort this out until we give people back the confidence to reclaim public space. We are endlessly deferring to machines the duty of making sure that our public space is safe, because people feel too nervous to do anything, and because citizens feel disempowered. My instinct is always to put responsibility into the hands of people and not substitute machines."

Mayor Johnson is on a roll. A little over a year ago, it was an open question whether he was to be taken seriously. He was articulate, well known, and very funny on Have I Got News for You, but his political career seemed to be up a blind alley. David Cameron thought him too erratic to hold a seat in the Shadow Cabinet and he was far from being Cameron's first choice of candidate in the London election.

Now, after a year as the most powerful Conservative politician in the land, the tousled-haired one has shown that he can run a big political machine effectively, and a much bigger one than Cameron or any other shadow minister apart from William Hague and Kenneth Clarke has run.

It no longer matters whether his old chum from Eton College and Oxford University thinks he is cabinet material, because he has his own power base from which he fires the occasional broadside across the ship that Cameron and the shadow Chancellor George Osborne run, and there is nothing they can do to silence him.

The 50p tax rate that Alistair Darling is to impose on people earning more than £150,000 is one source of contention. Johnson thinks the Tories should scrap it once in power. Cameron and Osborne are wary of being seen to do favours for the rich.

"I completely understand what George's position is and David Cameron has spoken a lot of sense about this," Johnson said. "I just feel that as Mayor of London, I have to point out that London is full of fantastically creative businesses that need to attract the best talent from around the world. If you tell them you are going to take considerably more of their money away than they could expect in the competitor capitals, that's a poke in the eye for London." Then there was the manner in which Johnson sacked the Metropolitan Police Commissioner, Ian Blair, without forewarning Cameron. One theory is that it was done on the spur of the moment because a conversation with Blair went so badly that the Mayor decided that they simply could not work together. "That supposition is not correct," he said, with unusual brevity. If so, why did he not forewarn Cameron? "I don't want to go back into the details of all that."

Johnson has used his pulpit to call for more grammar schools, which is not Conservative party policy. When challenged, he says he does not want to return to the pre-1970s set up, with the majority consigned to "secondary modern" sink schools. Instead, he dresses an idea much loved by the Tory right in the language of the left, no doubt to make it palatable to Independent readers.

"As a society we need to recognise that our ruling class is engaged in a massive act of hypocrisy. They either use their economic power to buy housing near the best schools, or they use their economic power to buy tuition for their kids out of hours, or they use their economic power to buy fee-paying education for their kids. What we have is plenty of ways that money can buy you educational advantages, but not enough ways in which brain can get you one," he said.

Even when they are expressed in the language of a radical, each of these displays of independence are precisely calculated to appeal to a large constituency in the Tory party who think Cameron is being too cautious, straining too hard to hold the middle ground, but who will go along with his strategy as long as it offers them the prospect of power. But more Tories are seeing Johnson as the default successor to Cameron if things go wrong.

To be in position to be a contender, Johnson would have to be back in Parliament. This means that before he comes up for re-election as Mayor in 2013, Johnson, who is 44, will have to calculate where his long-term future lies. So, unlike Ken Livingstone, who wanted to go on and on being Mayor, Johnson is studiously vague about whether he even wants a second term. "If I think I'm doing the blindest bit of good, then of course I'm going to think about running again," he said.

Questions about whether he sees himself as Prime Minister produce a more obscure answer featuring a Roman ruler called Cincinnatus who returned from retirement by popular demand. All ambitious politicians have to find a way of evading the question of whether they want to be Prime Minister, but no one should be fooled by Johnson's tendency to joke or that air of absent-minded fogeyness he cultivates. There is no ceiling to the Mayor's ambition.