He came to toast a remarkable victory, to celebrate an extraordinary electoral success. In his debut address, Labour’s leader referred to it often, speaking of the mandate he’d won – its sheer scale, finding new ways to count the colossal votes he’d racked up. This was a triumph to savour, one that heralded a new politics.

The election result Jeremy Corbyn had in mind was, of course, the one that had made him his party’s unexpected leader. Of an earlier ballot, the small matter of the general election that handed David Cameron his first overall majority, there was no mention. For a glorious hour, 7 May was erased from history, its place overwritten by 12 September.

Such a rosy view of the events of the last few months delighted his audience. They revelled in his witty jab at the commentariat, suggesting the media scribblers were as misguided as a sports reporter who sees a football club win 160,000 new fans, the ground packed out with young and optimistic supporters – only to declare “I don’t know how this club can survive a crisis like this.”

The hall laughed warmly, enjoying the chance to forget that Labour had in fact suffered a second massive defeat in May, relegated for at least another five seasons.

And because 7 May had been eclipsed by 12 September, there was no need to explain what went wrong at the general election or how it might be reversed. Corbyn did not address the reasons voters have repeatedly given for not backing the party. He did not speak of immigration, except in the context of the refugee crisis. He did not speak of welfare, except with a promise to save on housing benefit by lowering rents. And he did not mention the deficit or Labour’s ability to run the economy at all. Ed Miliband forgot to talk about the deficit last year, but at least he had planned to. The omission by Corbyn was no memory lapse.

There were moments when the new leader pointedly tried to reach beyond the Labour faithful. He raised the plight of the self-employed, getting by with no holiday or sick pay. He mentioned small business. He even reclaimed the word “aspiration”, saying that Labour wanted the best for all children, not just the few.

But those were exceptions. Most of the speech was aimed at those in the hall and the wider Labour family. He spoke of the things that concern them and which have concerned him through a long life of dogged activism. There were passages about the party’s own decision-making processes and how they would change. Dreamily, he imagined a world in which thousands would spend their time the way he has spent the last 30 years. “What a tremendous opportunity for our Labour party to be the hub of every community. The place where people come together to campaign … to explain and talk to their neighbours about politics.” That’s a pitch unlikely to resonate with large sections of the British public, those who tend to take Oscar Wilde’s view of the trouble with socialism: “that it takes too many evenings”.

Jeremy Corbyn's speech: what he said – and what he meant Read more

And yet this seemed to be Corbyn’s focus: to change politics, rather than to change the country. Tellingly, he concluded with a quotation from Keir Hardie, one in which Labour’s founder said he had dedicated his life to “trying to stir up a divine discontent with wrong”. Much of what Corbyn said in Brighton was about campaigning differently, as if that were an end in itself. Governing – power – almost seemed secondary.

For committed Labour supporters, Corbyn struck several dependable chords. He spoke of the injustice of those about to lose tax credits; the shortage of affordable housing; the importance of mental health; human rights abuses in Saudi Arabia; Syria; the case against the renewal of Trident. In conferences past, Corbyn would have spoken on each of these themes at consecutive fringe meetings. Now he had the entire hall and a battery of TV cameras watching him. But while few would deny that each of these subjects matter, they hardly amounted to an offer for the country – to the middle earners who might not be reliant on tax credits nor even, candidly, care much about those who are.

The optimists will say that can wait: there’s four and a half years for that. The pessimists will say that the conference speech marked the end of Corbyn’s getting-to-know-you period with the British electorate. That this was his last chance to make a first impression.

And, judged purely by the standards of political tradecraft, Corbyn’s speech was not a success. If Winston Churchill once complained that the pudding he had been served lacked a theme, he would similarly have turned his nose up at Tuesday’s fare. There was no narrative arc, no discernible structure at all. Even though it was scripted, Corbyn seemed to freewheel, moving from Saudi Arabia to trade union rights to broadband to refugees to Labour’s surging membership to an admirable, and loudly applauded, denunciation of cyberbullying and online misogyny to voter registration to housing to mental health and back to housing again. It was not so much a laundry list as an exercise in word association.

At one point, he read out what seemed to be a stage direction, saying aloud words that had been put there to guide his delivery: “Strong message here,” he said, interrupting his own sentence.

More troublesome, not long after he had sat down it emerged that passages of the speech were all but identical to a text previously written and publishedby blogger Richard Heller, and recently submitted by the writer to Team Corbyn. Those included the speech’s most stirring section, a rousing insistence that none of us need be resigned to our fate: “You don’t have to take what you’re given.” Except in this case, it seemed, Corbyn had done just that. Still, the row looked set to be fleeting: Heller himself is untroubled by the Labour leader’s use of his words.

Besides, such things might not matter anyway. Some in Labour were worried that Corbyn might have a disaster, fall flat on his face and crumple in the spotlight. That didn’t happen. Instead he came across as earnest, committed and charmingly diffident. There was no macho swagger to his arrival; instead, he radiated a winning humility. He was gracious to his defeated rivals, especially Liz Kendall. He remained true to himself, not hiding the person who has spent a life trying to change the world by attending meetings. And for those sick of the besuited automatons who once dominated Westminster politics, he will seem like a breath of bracing fresh air.

More deeply, his call for a kinder politics and more caring society should resonate with those sick to their stomachs with the way things are. His defiant rejection of fatalism echoed the rallying cry delivered by Peter Finch’s bitter TV anchor in the 1976 movie Network, appealing to all those who are mad as hell and not going to take it anymore.

Still, the key question comes down to a number rarely uttered. Jeremy Corbyn won a mandate massive by the standards of a political party: 251,000 people voted for him. He believes that is the beginning of a transformation of the country. But 11 million people voted for David Cameron in May – even if few in Brighton like to mention it.