Pre-arrange an interview with Jeremy Corbyn, and he is far more engaging, disarming - even charming - than you might imagine.

He’ll sometimes tell you about a book he has been reading. He will occasionally poke gentle fun at his internal opponents.

He once told me his 2016 leadership challenger Owen Smith offered him the post of party president if he’d stand aside.

He then said in hushed tones, with a glint in his eye: “Of course I found out this post didn’t actually exist”.

He once took me through the history of a building society advertised in a hoarding behind him, as he warmed up for an interview on the campaign trail.

And recently, he gave a colleague his top holiday tips for a visit to Mexico (his third wife, Laura Alvarez – whom he married in 2012 – is Mexican).

But often he is more thin-skinned, resenting in particular those who try to get an unauthorised word from him outside his front door.

He is fiercely protective of his privacy and that of his family. He would say he is open to scrutiny, but that he draws the line at intrusion.

In his acceptance speech as party leader in 2015, Corbyn denounced the “appalling levels of abuse” that members of his family suffered during the campaign and he appealed to reporters to “leave them alone in all circumstances”.

And there are circumstances where Corbyn himself would like to be left alone.

He once chided Channel 4’s Cathy Newman and myself for talking over each other as we fired off questions to him.

Martyn Sloman - a member of Islington Labour in the 1980s - told me Corbyn behaved much the same way to party members as to the press. He was never rude or aggressive, says Sloman, but he didn’t like being challenged: “That was his weakness. He didn’t like criticism at all. He bridled at it.”

And some said his thin skin would need to transform into a rhino hide if he were to go from opposition leader to prime minister.

But did he really want the job? Or was he - as some critics suggest - more interested in moving Labour permanently to the left?

Lansman said that the Corbyn leadership had changed Labour irrevocably. “We are never going back to neo-liberalism,” he says. “That’s been decided forever - well, for a generation. The party is a fundamentally different party and there is no going back.”

And it’s certainly true that the party has changed rapidly under Corbyn’s leadership. Before the election, the levers of power in the party were controlled by his supporters.

If he was willing to be as ruthless, and as determined in the face of adversity, his backers believed he could lead a radical government.

But before becoming Labour leader, his appetite for power seemed to be rather limited.

In his Guardian interview in 2015 – when he got on the leadership ballot but before he won the contest – he said: “At my age I’m not likely to be a long-term contender, am I?”

He often sidestepped the direct question. Soon after becoming Labour leader, Corbyn chose to answer the question in this way: “The best type of leader is a reluctant leader.”

He certainly reflected long and hard when most of his MPs wanted to oust him in 2016, but he didn’t resign.

He has resilience.

And he made it clear that despite speculation he would have served a full term as prime minister if elected.

Some detractors questioned how far he would have been in charge if elected. They pointed to the influence wielded by advisers, such as former political commentator turned strategist Seumas Milne, and Andrew Murray, a veteran of the Stop the War coalition.

But this was dismissed by one insider, who said there is a myth of “the good king and the bad advisers” - they insist that Jeremy Corbyn knows his own mind and his staff reflect rather than mould his views.

There is a belief in his inner circle that “dark forces in the Establishment” would do whatever they could to stop him entering Downing Street.

There was a call for an investigation when the Times, in June, alleged that senior civil servants had questioned his physical fitness for office.

McDonnell, however, claimed that Labour’s leader was the “fittest person I know”.

But some opponents may have been closer to home.

Momentum has supported his leadership but has at times also shown its independence.

I’m told that its founder, Jon Lansman, hopes that John McDonnell will become the next party leader. But McDonnell himself recently told GQ magazine that the next leader should be a woman.

What is remarkable is that, on the brink of an election, in the bars, cafes and corridors at Labour’s recent conference, there was widespread speculation over who should be Corbyn’s replacement.

I was even told of a putsch that never really quite came to shove.

In July this year, leading Labour peers took out a newspaper advert arguing that Jeremy Corbyn “had failed the test of leadership”.

It was dismissed at the time as the predictable opposition of those ennobled by Corbyn’s predecessors.

But the initiative didn’t come out of the blue.

It was designed to give impetus to some on the left who were trying to sound out shadow business secretary Rebecca Long Bailey as a replacement.

Any potential plot quickly evaporated, but those mulling over whether or how to proceed wanted to clear out some of the key figures in the leader’s office too - and that part of the plan now seems to have come to fruition.

Jeremy Corbyn’s robust gatekeeper Karie Murphy - a close friend and ally of Unite’s Len McCluskey - was moved aside to a role in the party’s head office.

Some of the Labour leader’s supporters believed that a move to drain his authority was under way.

Corbyn’s position was also weakened by the announced departure of Andrew Fisher - his policy guru who managed to be close both to the Labour leader and the shadow chancellor.

In a letter to friends - seen initially by the Sunday Times and subsequently by the BBC - he denounced “a lack of professionalism and competence” in the backroom operation. He says that, while he hopes he is proved wrong, “I no longer have faith that we can succeed”.

Corbyn's pitch at his annual conference was that he could bring a “different type of leadership” to politics.

And his supporters insisted that after the divisions of the Brexit debate, it was this serial rebel who was best placed to unite the country.

His pre-election catchphrase was “trust the people”.

We didn't have to wait long to find out if they were willing to trust him.