It is no understatement to say that Keir Starmer’s speech in Brighton on Wednesday, as he faced down hecklers furious at his repudiation of Jeremy Corbyn, gave us one of the most electric half hours a British party conference has seen in decades. And this truth is only slightly diminished when you consider it took him 90 minutes to do it.

It took seconds from Starmer’s arrival on stage for the first protest to start up. The Labour leader, we had been assured, wasn’t going to mention his predecessor. So someone else did instead. “Oh, Jeremy Corbyn,” a lone voice sang. What would happen next?

Starmer ploughed on with his speech. Possibly he was unaware — it can be hard to hear heckles on the platform, apparently. But more interesting was the response of the rest of the conference, as the singer was shouted down by their neighbours.

Conference speeches are loaded with more significance than they can generally bear. If they are remembered at all, it tends to be for a single phrase or moment of drama. No one thinks Starmer is much of a phrasemaker, but there were hopes we might get drama. One journalist thought he should get Tony Blair and Gordon Brown on stage together, though if Starmer could do that, he’d deserve the Nobel Peace Prize. Another suggested the Labour leader should read out the names of guilty party members, who would then be arrested.

But most of the conference had been a warm bath of self-reassurance, summed up by the Mirror’s disco the previous evening, which had barely played a song recorded after 1997. Would Starmer follow that pattern, and simply ignore the terrible situation that Labour was in?

He didn’t. After some words on the fuel crisis, clearly inserted at the last minute, he turned his attention to his own party. The last election had seen “our worst defeat since 1935”, he reminded them, before seeming to suggest that this was actually a lucky escape, as he thanked activists for saving the party from “obliteration”. By this stage, he’d already been interrupted several times, with shouts of “Vote Corbyn” and another delegate blaming Starmer for pushing the party to back a second Brexit referendum.

“Normally at this time on a Wednesday, it’s the Tories who are heckling me,” the leader replied, and the conference rose to its feet to applaud. It was a scripted reply, of course. His team had written half a dozen for him. What, Starmer had asked speechwriter Phil Collins, should he do after those ran out? “Tell them to fuck off.”

Things didn’t get that far, disappointingly. The key moment came a few minutes later, when, as the leader talked about watching nurses care for his mother, a woman near the front stood and began yelling at the platform. Starmer looked out at the hall. “Shouting slogans, or changing lives?” he asked, and they stood again, to cheer him.

There was a lot on Starmer’s family. One of his problems as a Labour leader is that he comes across as a posh lawyer. This is because he is a posh lawyer. But he does come from a far more “Labour” background than is generally appreciated. “My father was a tool maker,” he said. “Although in a way, so was Boris Johnson’s.”

The sections of speeches where leaders talk about their parents are tricky. Gordon Brown talked about being a son of the manse, David Cameron about an evening stroll around the village with his dad. Will the prime minister next week also treat us to lessons he learned from his father? “My boy, if you can only do one thing, let it be this: never let your mistress meet your wife.”

Even the hecklers seemed to get bored, silent for long periods and then increasingly esoteric. “Free Julian Assange,” shouted one

Parts of the speech were very moving. There was definitely something in the Sketch’s eye when Starmer talked about John and Penny Clough, who had come to see him when he was a prosecutor, to talk about their murdered daughter. The screens showed the Cloughs sitting in the audience next to Doreen Lawrence, the mother of a murdered son.

And it had moments of subtlety. “It’s easy to comfort yourself that your opponents are bad people,” Starmer told a party that had spent several days doing exactly that. “But I don’t think Boris Johnson is a bad man. I think he is a trivial man. I think he is a showman with nothing left to show. A trickster who has performed his one trick. Once he had said the words ‘Get Brexit Done’ his plan ran out.”

But goodness, it was long. Hands spun round a clock, pages were torn from a calendar, the trees turned brown then lost their leaves then turned green again, and still he was talking about industrial strategy. Even the hecklers seemed to get bored, silent for long periods and then increasingly esoteric. “Free Julian Assange,” shouted one.

Starmer’s team say the length was the result of an unexpected number of interruptions for applause: a speech that was an hour in rehearsal ended up being half as long again. There certainly were a lot of standing ovations: twice for the England football team (and other home nations and sports too) for the military, for the idea of patriotism. They even found themselves clapping for Tony Blair. Not by name, of course, but his works.

As the speech closed, Starmer turned back to the Conservatives: “If they are so bad, what does it say about us? Because after all in 2019 we lost to them, and we lost badly.” There was a murmur in the hall. The Labour Party doesn’t know the answer to this one. But finally someone had asked the question.