Against the milestone today of his first 100 days as Labour leader, we are having to reassess the common view of Jeremy Corbyn. The accidental leader he may be; there is no pretence that he tilted at the job with any belief that he might get it. But the notion that he doesn’t really want it now seems wide of the mark.

He has confounded the expectation, and for some the hope, that elevated to high office is a living, breathing version of Private Eye’s lefty halfwit Dave Spart. Both sport beards, but there the similarity peters out. Spart harangues the ear with gobbledegook intelligible to the splinterists of the People’s Front of Judea and the Judean People’s Front, but unintelligible to anyone else. Corbyn, by contrast, outlines his position to ordinary people and the media very well, when permitted to do so unabridged. The ability to make his case, and to show certainty as to what that case is, allowed him to shine against the dull backdrop of the leadership campaign, in which he secured 59% of the vote. It serves him well whenever he submits to one-to-one inquisition with a Humphrys or a Marr.

A hundred days of spotlight have shown Corbyn to be a thoughtful, precise figure. He has wobbled, but having endured quite a media battering he has never fallen down, as those who look at him and see disaster hoped he might.

We were told he would be the dour, humourless lefty; and again he has been a challenge to expectations. Just last week he was to be found wisecracking with his tormentors from the mainstream media and pouring them drinks at the party’s Christmas get-together. The event was “on one level yours and my worst nightmare,” he told them, which was both self-knowing and right. At Labour’s internal Christmas drinks party, he courted controversy by channelling Enver Hoxha, Albania’s communist dictator. “This year will be tougher than last year,” he said. Like many who seek to entertain, he’ll go to the edge of propriety for a laugh.

Detractors are forced to concede that his emergence has brought with it a new vitality

There is success on his terms and on the terms of the many thousands who have been attracted to and energised by his rise. Detractors are forced to concede that his emergence has brought with it a new vitality, a new energy to local parties that were demoralised and withered. He would have been pleased at the outset to have survived 100 days. He has more than achieved that, and gradually we see roots of permanence. And yet, at this point, it isn’t quite enough.

One hundred days is too short a time to expect completion of a reconstruction project of this magnitude, but surely it is ample time to see the first inklings of what, if any, long-term strategy exists.

Without question, Corbyn takes seriously his mission to bring hope to those who have lost faith in politics; those jaded by the requirement to fall in behind leaders with whom they only partially agree. The connection with them, as he spoke out against Trident, stood firm in his support for the Stop the War campaign and above all, as he opposed the bombing in Syria, has been direct and immediate. When he failed to balance his shadow cabinet with talented Labour women and gave the top jobs to men, they attributed the error to teething problems. When he did not sing the national anthem during a Battle of Britain commemoration service – prompting the outrage of the rightwing press – they saw it as the same diversionary fluff that surrounded whether he might, as a privy councillor, bow before the Queen.

When he was castigated for not bowing low enough at the Cenotaph on Remembrance Sunday, with the precise angle of the bow subjected to pinpoint measurement, they took that as further evidence of media mendacity. When he said he would never press the nuclear button – allowing critics to cast him as weak on national security – and then appeared to suggest, prior to self-correction, that he might not a support a police shoot-to-kill policy, even to prevent a Paris-style attack, admirers knew precisely where he was coming from.

They liked his nous as he called for the government to scrap its questionable prisons contract with the Saudis – occasioning a U-turn. They applauded his championing of voters’ submissions on core-left issues such as austerity and welfare at prime minister’s questions. They have bought the brand and the brand does what it should.

Hence there is complete, understandable and legitimate brand loyalty. Yesterday’s Opinium/Observer poll showed 56% of all voters believe the Labour leader “sticks to his principles rather than just saying what people want to hear”, compared to 24% who disagree. That’s an admirable statistic. Many a politician would hanker for it. Only 34% felt the statement was true of David Cameron. But here’s the rub; 57% of all voters – including 30% of Labour supporters – thought it unlikely that Corbyn will lead Labour into the next election and only 54% of Labour voters thought he would be the best prime minister were he to win. He is a success on his terms and on the terms of his supporters, but these aren’t terms sufficient numbers can sign up to.

So what might happen in the next 100 days? On the evidence of the first 100 days, that’s a question beyond the most talented soothsayer, but as the days pass, maybe word will emerge of a plan. How to consolidate Corbyn’s strong position into long and stable rule without driving the party deeper into division and factionalism? How to assuage the fears of MPs who fear the welcome enthusiasm of the revitalised grassroots will lead, if undirected, to localised civil wars and purges? How might he show determination to take all sections of the party with him, especially – given his shadow cabinet selections – its women? How to project a party strengthened and energised by the left into a progressive force that can appeal to voters outside those parameters, and can – at some imaginable point – win an election?

No one expects the completed project, but many will now reasonably ask to see the blueprint. With the argument about who has power now settled, he has a responsibility to show the broad Labour church, and then the broader electorate, how effectively he will use it.

“Am I looking at the next prime minister of Britain?” Andrew Marr asked him last month. “I hope you are,” he said, but he never really looked as though he believed it. He never does. Interviewers routinely ask the question because they and others need to discover if dominance within the party is in fact the height of his ambition. In the next 100 days, we may all know.