Alexander Boris de Pfeffel Johnson:

less a name than a cast list. Less a name, in fact, than a brand. Yet, like a stand-up comic or a family pet, the Mayor of London is known to friends and enemies alike simply as Boris. That, plus his shambling buffoon act, might be his greatest achievement.

In reality, Johnson is a deeply serious - or at least seriously ambitious - Tory politician. The BBC's Eddie Mair might have reduced him to fluff and bluster in a forensic interview last year, but this character - the only word that fits - was undaunted. The moment was emblematic.

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Standing revealed on national TV as "a nasty piece of work" might have crushed a smaller ego. Instead, Johnson managed to make himself sound like a jolly good sport, taking his lumps as a chap does while defending the BBC's right to call him profoundly dishonest, bereft of loyalty, and worse. Through long experience, the mayor knows that a few tedious facts are no impediment to a career.

So it has proved. Breezily breaking a dozen promises, Johnson now says he has a hankering to return to Parliament in 2015, a year before his second spell in charge of London is done. The seat of Uxbridge and South Ruislip, where Sir John Randall means to retire with a majority of 11,216, springs to minds. The certainty that David Cameron will resign if the Tories fail at the next UK General Election is not overlooked.

Obligingly, London newspapers have provided polling to show that most Conservatives - not to mention "the country" - are Batty for Boris. Last weekend, The Sun On Sunday published numbers showing that 34 per cent believe Mr Johnson should replace Mr Cameron, with fully 50 per cent of Tories taking that view. On Wednesday, London's Evening Standard printed figures to justify the claim that "The Conservatives could have a Commons majority within their grasp if Boris Johnson were leading the party".

If you happen to be of that persuasion, and don't mind a confessed fabricator of quotes and fibs, this might be good news. What about the rest of us? If one Etonian supplants another, and if the de Pfeffel clan take a lease on Downing Street, what becomes of the political landscape in this Britain?

One issue is obvious. Mr Johnson's party has made solemn promises of "more powers" for the Scottish Parliament if we vote No in September, and if someone - not us, at a guess - returns them to government at Westminster in 2015. How much more reassurance could you need? Well, there's always the word of Boris.

Talking to The Mail on Sunday last weekend, London's mayor said there was "no need" for further devolution. "Ever more things we are giving Scotland," added Mr Johnson, "but for no reason we are promising the Scots more tax-raising powers. There's no need to do it".

He then expatiated a little on the city-state theme that has become popular with all the Westminster parties as they struggle to justify the power of London in British life. The Scottish example was presented as the problem, however, rather than a solution.

"What has England ever got out of this devolution process?" asked the mayor. "If you want to have growth in the English cities then you should do what Manchester wants, what Liverpool, Leeds, all of us want - and that's give us more tax-raising powers."

To Mr Johnson and his supporters, this probably sounded like a fine way to begin to quell the Ukip insurgency in the north of England while dealing with the problem of London. As ever, the mayor was speaking off the cuff. As usual, he could no doubt disown his words in the instant between heartbeats.

Still: this is a man with pretensions to lead a party that has made serious and specific promises ahead of Scotland's referendum. This is a man who has a decent chance of becoming Prime Minister when the dust of an independence vote has settled. His considered opinion on the making of promises? "There's no need for it."

A parallel case presents itself with the Johnsonian view on Europe. He's not rash enough to call for a UK withdrawal. He is bold enough, nevertheless, to set near-impossible terms for a "new relationship" and happy to promote the idea that Britain "could have a glorious future" outside the Union. Once again, this bolsters Tory defences against Ukip. Once again, it panders to back-bench opinion. But this is a man with a naked desire to be Prime Minister of Britain and, when he remembers, Scotland.

Try the possibilities. There is a No vote. Mr Johnson tears up those "more powers" pledges and steers Britain towards its "glorious future" outside the EU. Who'll be content with that? A big portion of the English electorate, perhaps. The Scottish minority, once it gets over the fact that it has been taken for a ride, will be wiser, for a while, but less than enthused.

Never fear: the vote will be Yes. Then we will only have to contend with a Boris Britain that treats the rump UK's EU membership as none of the neighbour's business. Economically, this could be tricky. In terms of the relationships between countries it could be comical or worse. Mr Johnson is a serious candidate as a future PM, but nothing he says involves a future that is better or together. As he said: "What has England ever got out of this devolution process?"

His ambitions are plain and perfectly realistic. Those polls attest that he is vastly more popular, in the south-east of the island, than George Osborne or Theresa May. Boris and his balderdash play extremely well in the Tory heartlands. No "nasty piece of work" is discerned by that constituency. For his backers, Mr Johnson is the authentic, charming voice of their Britain. Should he let them down, there's always Ukip.

It needs to be better understood. The man who means to be the next Tory leader treats promises of "more powers" for Scotland as an impertinence. The man who would be Prime Minister, whether our vote is Yes or No, regards your European citizenship as of no great importance. His absence from the Better Together referendum campaign is not, in that context, much of a mystery.

But let's be fair. The Evening Standard has not quite boasted that Mr Johnson could beat Ed Miliband. The next UK General Election is not the mayor's primary target, in any case. As ever, he seeks the crest of a populist wave: a bit of euroscepticism, a little telling the Jocks where to get off. In the Tory heartlands he knows so well, where few think BoJo bizarre or disturbing, it goes down well. Ponder that.

Vote No for a Tory party led by Mr Johnson? You can doubt Scottish Labour is telling such a tale on those famous doorsteps. Nevertheless, if independence is rejected and Boris is the first pick of the blinkered, there will be no alternative. Outvoted is outvoted. Volunteering to be outvoted for the sake of a nasty piece of work is, of course, what Britain is all about.