During the run-up to the EU referendum, which the Westminster Village believed Remain would win, Boris Johnson was confronted with a choice.  It is said that his safest option was to stick with the winning side.  This is wrong.

Johnson will have known what now is sometimes forgotten – that David Cameron had pledged not to fight a third general election as Conservative leader.  Party members were emphatically pro-Brexit and so, come the leadership election, would be likely to back the most Eurosceptic candidate.

So the then ex-Mayor had his angles covered either way by backing Leave.  If Remain won, Cameron would need to heal the Party’s campaign wounds and, consequently, would also need Johnson in a major Cabinet position – nicely placed for a leadership contest in 2017 or thereabouts.  In his autobiography, the former Prime Minister said that he had defence in mind.

And if Leave won, Johnson would be excellently placed in the 2016 contest which would follow.  Which brings us to the second time he chose the least risky option.

For when Michael Gove broke faith with him, and declared that he would stand for the leadership himself, Johnson himself could have thrown the dice and stayed in the race.  Instead, he and his team were ultimately swayed by the numbers – in other words, by the damage that Gove’s candidacy was doing to his support.

Johnson’s calculation will have been that if he didn’t stand, a door might open in future.  But that if he did, it would risk closing forever – since no Tory leadership contender other than Michael Howard has won a contest having previously lost one.  (And that was a special case: he was elected unopposed.)  Better a live dog than a dead blonde lion.

This gamble paid off in the long-term and indeed in the short.  For Theresa May concluded that Johnson had behaved honourably and Gove dishonourably.  The latter wasn’t appointed to her Government first time round.  The former was made Foreign Secretary.

This takes us to his third prudent decision – namely, to resign from that post in the wake of May’s Chequers Plan.  He did not want to quit.  Senior politicians seldom do – at least, so soon after a promotion to a great office of state.  But Johnson saw that once David Davis had resolved to resign he had little choice but to do so too, or else lose his Brexiteering credibility with Party members and Conservative MPs.

So he stepped down – and shot up immediately to the top of this site’s future leader survey, thus helping to establish the platform which supported his candidacy the following year.  From the moment he left the Government, he was set to be the members’ choice if May fell.  Winning the backing of Tory MPs was a more hazardous enterprise.

In any event, he succeeded in squaring both, became Party leader and Prime Minister, and made the fourth in this series of choices.  Taking the whip off 21 Conservative MP rebels, seven of them former senior ministers, looked like a rash decision.

For after all, it made his Government very much a minority one.  It had been preceded by the prorogation gambit, which was upended by the Supreme Court, and was followed by Commons defeats – after which Johnson decided that his best course was to break his promise to deliver Brexit by the end of October last year.

He and Dominic Cummings, however, had come to see that the removal of the whip from the 21 was unavoidable after the breakdown of discipline under Theresa May, and that the only strategic option open to him, in order to avoid a drift to a second referendum, was to press for a general election.

The last Parliament would not deliver Brexit (it voted at Second Reading for his revised Withdrawal Agreement but against the timetable for debating it).  So it followed that it would have to be replaced with one that could – to “get Brexit done”.  This duly happened.

This brings us to his final choice of the safer of two options, and this one really was a no brainer. This site believed that the negotiation with the EU over trade would end with a deal, though our faith was tested at times.  But there was no way of knowing.  Johnson resolved not to repeat May’s mistake if he agreed one of becoming ultimately dependent on the goodwill of Labour, which duly let her down.

Deal or No Deal, the Prime Minister appears (and the following verdict is a bit provisional) to have decided to take no risks with Party unity.  That meant taking “control of our laws” – the first and most crucial of a series of specific Conservative Manifesto commitments.  Which meant keeping the European Court of Justice out of any trade agreement.  This appears to have been accomplished.

We apologise if this article gives the impression that these five choices were easy ones.  They were not.  There was a case against each of them; historical inevitability is a Marxist delusion, and all might have turned out differently.

Nonetheless, a thread runs through them which will surprise some of our readers, and up to a point surprises even us.  Indecisive, a shopping trolley, prone to change his mind, unstrategic, unpossessed of an ideological compass, undisciplined, almost impossible to read, unreliable – you have heard all this about the Prime Minister before, including sometimes from this site, and will doubtless do so again.

But when it has come to Brexit, this complicated, contradictory man, not unfairly called The Gambler in Tom Bower’s new biography, has kept it simple – and, if the gambling metaphor applies, has repeatedly chosen the option on which he was less likely to lose his shirt.  That defies so much of what he’s about as to require further explanation.

Ours is also simple.  We presented all five of these choices earlier in a tactical light – and, goodness knows, Johnson is not the man to have made them without regard to his self-interest.  But something else has been going on.

Maybe that exercise in writing a case for both Brexit options really did decide him.  (“How do I know what I think until I see what I say?” – as Auden put it.)  The Eurosceptic take of his former wife, Marina Wheeler, will surely have made an impact.  But perhaps in the end his instinctive twitch against restraint won out.

For this former Brussels correspondent always saw the EU as a lumbering, slow-witted, unresponsive behemoth – trampling voters and referendums in its wake.  At any rate, once he made up his mind for Leave, he never lost sight of the essentials: that’s to say, taking back control.

The Europe issue caught Margaret Thatcher before her party was quite ready for it.  Her ousting ensured that it was, and helped to destroy John Major.  Cameron and May were direct casualties.

Of course, Johnson has been lucky in his timing.  But he has made the most of it.  He has been a bit like the rider of an unruly horse.  Patriotic populism takes a variety of forms – not all of them benign.  The most astonishing aspect of Johnson’s leadership is that he has kept astride that bucking charger, and rides it in a familiar direction.

His is a high-spending, pro-NHS, green-flavoured, migration-liberal government – more in the old Tory tradition, in an eclectic kind of way, than a Thatcherite one.  That he has channelled some of the passions behind Brexit into an established political vehicle is extraordinary.  It is a historic achievement on the scale of his Odyssean sense of himself.  Not even future failure, if it happens, can erase it.