Half an hour before Rachel Reeves was due to speak at Labour conference, the stewards in the vast hall were busy guiding people to seats. Diplomats here, journalists there, business delegates into that section. At both entrances there was a dense crowd of people anxious to be there for the big moment. The mobile phone signal on Liverpool’s docks had collapsed under the weight of visitors.

On the stage, Jonathan Reynolds, the party’s business spokesman, was warming the crowd up. Reynolds has the air of a kindly geography teacher and his speech, which was either about gigafactories or the formation of ox-bow lakes, was well-received. But he wasn’t the main event, and he knew it.

She’s widely believed to have had elocution lessons

Before Reeves came on, we got a little video, showing her transformation from neatly dressed schoolgirl to immaculately turned-out Shadow Chancellor. Here she was making a speech in New York, and here she was in Paris, and there she was visiting Congress. “See,” the message was, “she looks the part.” It’s easy to sneer at the stuff but it matters. One of the problems faced by Ed Miliband was that it was simply very hard to imagine him as prime minister. Reeves, Labour was telling us, has been a boring nerd since her earliest days. She’d fit right in at the Treasury.

She arrived on stage to thunderous applause. She seemed, standing there, to have every muscle tensed, her back completely straight, her teeth in a fixed grin, as though a passing headmistress had just told a girl down the line off for slouching. Her enunciation was precise. She’s widely believed to have had elocution lessons, and certainly her accent is different from that of her sister Ellie, also a Labour MP, who was sitting on the stage watching.

Of course she was nervous. Who wouldn’t be, facing that hall? Who wouldn’t be, knowing that this year, the country is paying attention to Labour, that for all the crowds and the sense of the imminence of power, a mistake could blow it all up?

But in the room, at least, they were on her side, cheering her from the first sentence. “For too long, we have gathered in these halls with the power to talk, but not the power to do,” she told them. This is always Labour’s internal tension, the debate about whether it is better to stay pure or to compromise with the electorate and win. After 13 years, they’ve made their minds up.  So, curiously, have the Conservatives, already relishing the prospect of long arguments about the best way to give tax breaks to married couples, untroubled by the prospect of having to implement anything. “So ready for opposition,” as Reeves put it, “that they are behaving like they are already there.”

The next Labour government is going to deliver  a series of highly entertaining show trials

This was her third conference speech as shadow chancellor, and by far the most accomplished. It was flattered by the comparison to last week’s effort from the actual chancellor, Jeremy Hunt, which wasn’t so much a speech as some remarks jotted on a napkin as he made his way into the hall. This felt like listening to Gordon Brown in his pomp: an economic argument developed into a political case. If a conference stand collapses on Keir Starmer tomorrow, Reeves has already made her pitch for his job.

The criticism is that as with Brown there was the sense that the solutions to the nation’s problems fitted neatly into the Labour worldview. There was a handy set of enemies: private schools, energy companies, internet giants – the conference features much pleading advertising from Amazon and Uber telling us what wonderful employers they are – and non-domiciled tax avoiders. The audience clapped and cheered for it all. These were “hard choices, but Labour choices,” Reeves said, which means they’re hard for people who aren’t in Labour.

There would be no more trickle-down economics, she said. Instead we’d see “growth from the bottom up and the middle out”. Those of us in middle age are already achieving both.

There was some intense politics, too. An incoming Labour government will probe the “carnival of waste” over Covid contracts. “I want that money back,” she growled in what must have been a deliberate echo of Margaret Thatcher. It’s not just the Covid cash that will be endlessly picked over. She seized a gift handed to her by Rishi Sunak. If HS2 had gone so horribly over budget, she said, it needed an inquiry. She didn’t say what that would look like, but we can guess: endless hearings, discussions of decisions by Conservative ministers, the release of poorly-judged memos, and a report shortly before the general election after next. The next Labour government is going to deliver  a series of highly entertaining show trials.

By the time she’d reached the end, she had relaxed. There was another standing ovation, a kiss from Starmer and a long hug from her sister.

On the screen, they played out an endorsement from Mark Carney. It’s not ideal that a former governor of the Bank of England is picking sides, but the next election is going to be a rough one. Elsewhere, Sunak had broken the traditional conference truce by doing a public event and giving an interview to Radio 2. His message was that the country needs a new direction. In Liverpool, Labour agree.