Rather rashly, Boris Johnson published The Churchill factor: How one man made history in 2015. It was without historical merit, or intellectual insight, but Johnson did not intend readers to learn about Churchill. The biography was not a Churchill biography but a Johnson campaign biography, where we were invited to see our hero as Winston redux.

Both ignored party discipline and conventional routes of advancement, after all. Both were great company. Churchill stayed in the wilderness for years making a fortune from journalism, and so has Johnson. Churchill was a man of principle and so is…

Hold on. That doesn’t work. It doesn't work at all. For when we talk of principle, the elaborate scaffolding Johnson has erected around himself, the scenery and props, the spotlights and the cameras, fall with a thundering crash. All that remains on stage is a jobbing actor who can play any part convincingly except himself.

The cult of Churchill can be remarkably selective. Certainly, Churchill and others fought appeasement. But he was also the most implacable of diehard imperialists. But I will give him this: Churchill meant what he said – and was prepared to suffer when his beliefs were out of fashion.

Johnson believes in the advance of Johnson. That’s all there is. There’s nothing else. Most politicians, and many of the rest of us, are ambitious, of course. But politicians normally hope to advance a cause as they advance themselves. Johnson would have you believe that he is breaking with the establishment, risking all, because of his sincere conviction that we must advance the cause of saving Britain from the European Union.

His colleagues do not believe him. Nicholas Soames has called him a liar on Twitter. Jerry Hayes called him a 'copper-bottomed, hypocritical little shit.' The wonder of it is that they may have been understating the case for the prosecution.

After the Times fired him for making up stories, Johnson ended up as the Telegraph’s Brussels correspondent. Once there, he was seduced by the most corrupting desire to afflict a journalist: the urge to give readers what they want. His tales of the EU punishing the rubber industry for making undersized condoms or ordering the straightening of bananas were so flimsy that, like dandelion puffballs, they collapsed with the first puff of scrutiny. They were a hit with his right-wing readers, but no one who knew him at the time thought that Johnson believed what he was writing. David Usborne, the Independent’s man in Brussels, told Johnson's acidic biographer Sonia Purnell:

“ He played the Telegraph game brilliantly [and] compromised his intellectual integrity to get on. I assume that he has done that in the rest of his career.

Curiously, when he entered parliament in 2001, Johnson stopped playing the right-wing nationalist from the Telegraph foreign desk and presented himself as liberal Tory. Chris Cook, an aide to David Willetts, told Purnell:

“ He was clearly not on the right wing, but actually quite europhile in Tory terms. He liked to come into our office to gossip and bitch about the right-wingers he thought had screwed up the party.

As Mayor of London, Johnson never called emergency conferences on the alleged EU tyranny, which surely must have fettered him, if it was as oppressive as he is now claiming. He never allied with Daniel Hannan, Charles Moore, Nigel Farage, George Galloway, Bill Cash and the rest of the 'out' crowd. The subject was of no interest to him – until he returned to Parliament to concentrate on the sole subject that does interest him: the leadership of the Conservative party.

If you doubt his slipperiness, examine his supposed declaration of support for withdrawal in 2016. It is not as unequivocal as it seems. A crucial line tied Johnson to a fantasy pushed by Dominic Cummings and Matthew Elliott of the Tory campaign group Vote Leave.

“ There is only one way to get the change we need and that is to vote to go, because all EU history says that they only really listen to a population when it says no.

We will vote to leave, in other words, but we will not actually go, because the EU will give us more.

To Johnson watchers, his shiftiness was no surprise. At Oxford he ran for the presidency of the Oxford Union as a Tory. He lost to a state school boy called Neil Sherlock, a liberal, who secured victory by mocking the old Etonian’s sense of entitlement.

In 1985, Johnson tried again and won, but now and all of sudden Johnson was a liberal too, who was opposed to Margaret Thatcher and in favour of proportional representation. Johnson has 'no core beliefs' an understandably flabbergasted Sherlock concluded. He would do anything.

The same disease afflicts him now. Charlatans from Donald Trump to Piers Morgan invite us to forget about our own concerns and revel vicariously in their career-advancing machinations, in much the same way that TV crime capers invite you to celebrate conmen and despise their gormless marks. So I beg you do not admire Johnson's manoeuvres as he climbs to the top over the bodies of his colleagues. Just understand them lest you find yourself his mark one day.

As I have said before, Johnson bears few resemblances to Churchill, and far too many to Winston’s shifty sidekick Brendan Bracken, who became propaganda minister during the war. Bracken too was careless with the facts. He invented stories about his childhood to con his way into high society. He was an energetic manipulator of the press in both Churchill’s interest and his own. (Whenever he gave dinner parties he instructed his butler to make up a story that the prime minister was on the phone and announce the news loudly to his guests). Evelyn Waugh couldn’t stand him, and in Brideshead turned Bracken into Rex Motram, who marries the wealthy but naïve Julia because 'he wanted a woman; he wanted the best on the market, and he wanted her cheap; that was what it amounted to'. Inevitably, he betrays her, within in months of the honeymoon.

'Rex isn’t anybody at all,' Julia concludes of Mottram/Bracken. 'He just doesn’t exist.'

A fine line, which applies well to Johnson. But I prefer a snub the historian Piers Brendon credits to an unnamed journalist who met Bracken in a 1930s club. Growing ever more infuriated by Bracken’s trickiness and double-dealing, the unknown hack cried

“ You're phoney! Everything about you is phoney! Even your hair that looks like a wig – isn't!

Bracken had a mop of red hair to match Johnson’s mop of blond. The next time I see our future prime minister I will give it a good hard yank, just to check.