Aficionados of movies about grifters will be familiar with the term “the long con”.

It’s the one in the background, the trick you don’t see until towards the end of the film when it is revealed as the plot twist. Could that be what consummate political conman, Alexander de Pfeffel “Boris” Johnson, is in engaged in?

The credibility of the theory I’m about to set out does rather depend on whether he’s a clever person impersonating a stupid one rather than the other way around. But let me explain.

Shameless as ever, after being hauled over the coals by parliamentary watchdogs for failing to declare £52,000 of outside earnings in time (imagine if a benefit claimant had done that), he took to Twitter on Friday to decry Theresa May’s Brexit deal.

For once, his argument was honest. I know, I know, that’s something you don’t see every day.

Boris Johnson apologises in parliament over failure to declare more than £52,000 in earnings

He said this: “The PM says she wants to let Parliament choose whether to enter the (Northern Ireland) backstop or extend the ‘transition’. This is simply not possible. Under her deal the EU has the legal right to stop us extending the transition and make us enter the backstop – whatever the PM or Parliament says.”

That’s a fair point, but it conceals a Brexiteer lie. It is that May’s deal could be renegotiated in Britain’s favour, or replaced with super Canada-style free trade thingumajig.

Neither is realistic, even were the EU, with other issues on its plate, not getting heartily and understandably tired of the games being played in Britain.

The choice is May’s deal, no deal, or no Brexit (after a referendum). To be fair, it’s not just Johnson that mendaciously claims otherwise. Jeremy Corbyn does it too.

Now here’s where the long con comes in. I suspect that Johnson knows that the last of those options represents much the best option for him.

May’s deal is on the carpet but no deal would result in a godawful mess and deep down I think he knows that. I think he probably realises that it would be bad for him and his career too.

The ideologues among Jacob Rees-Mogg’s laughably named “European Research Group” would consider the consequences worth it, regardless.

But Johnson? Given his ambitions? I think not. He knows sorting the aftermath would make the job of the occupant of Number 10 a horrible one, and probably a very short one.

He should also be aware that the electorate will not lightly forgive those who told them it’d all be alright when it proves otherwise.

Johnson is much better suited to making messes than he is to clearing them up.

But let’s say there is another vote, and Britain opts for Remain this time.

Theresa May would pretty much have to go. This has already been established. What then? Johnson’s stock looks low right now. He’s angered many of his colleagues with his conduct and has become a hate figure in large parts of the country. Cuddly Boris, the lovable rogue who became London’s mayor and fronted the Olympics, is long gone.

In the aftermath of a Remain vote, however, he could rise again. His pitch? “What Britain needs now is a leader who will stand up for our interests in Brussels. There is no appetite for further integration, and I’ll fight any attempts to push for it. There’ll be no more treaties on my watch either. You people who voted out, I’m the man who will make your voices heard now we’re staying in. I’ll keep a lid on the liberal elite too! Britain! Britain! Britain!”

That might play very well with his Eurosceptic party. It helps that there aren’t many alternatives among the hardcore Tory Europhobes. They’re a sorry lot. Johnson would also have the advantage, by contrast to Michael Gove, of no guilt by association with May’s failed deal (even though he initially supported it, before following David Davis out the door).

To be honest, the case I’m setting out makes me shudder.

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Johnson has proven himself to be a terrible person, a liar, possibly the worst foreign secretary in British history. Then there’s his cavalier approach to parliamentary rules.

If someone like that were a doctor, you’d run out of the surgery even if you were shaking with fever. If he were a pilot you’d pay whatever ridiculous sum Ryanair charges those who want to change flights. Yet according to the bookies, he’s the third favourite for the next person to do Britain’s most important job, behind only Corbyn and Gove in the lists.

So tell me that this isn’t a credible scenario.