This year’s Congress of the Trades Unions Congress (that’s right, it’s a Congress Congress, and if any delegates get their leg over, it’ll be Congress Congress congress) is in Liverpool. The slogan is “Winning at Work”, so it was appropriate that their big speaker on Tuesday was Angela Rayner, who has just got a big new job. The Labour party is, in general, winning at work just now, and she’d come to tell the unions how they could do the same.

By now, you felt, we must have got quite a long way down the TUC wish list

She opened by tickling their tummies, offering herself as an example of the good that a union can do. Rayner’s personal story, from pregnant 16-year-old to next deputy prime minister, is as impressive as any in parliament. It was a journey, she told the hall, that owed everything to a Labour government and a union. The first gave her a council house so she could find work, and second saw the potential in someone who had no qualifications, training her up and setting her on the path into politics. “I may have been born in Stockport,” she told the hall, “but I was raised in the trade union movement.”

Her audience knew all this, of course, but they were delighted to hear it again. Keir Starmer has a far longer history in Labour politics than Rayner, but seems to struggle to persuade people of it. No one doubts Rayner’s convictions.

Next, she gave them something to hope for. Recent anti-union laws would be repealed in the first hundred days of a Labour government! New laws would protect union representatives in modern workplaces! Blacklisting union activists would be illegal! There would be an inquiry into the behaviour of the police during the miner’s strike! By now, you felt, we must have got quite a long way down the TUC wish list.

But, Rayner said, “that’s not all …” She reached into her sack of presents. Unions would get a right of access to businesses. If this sounded a little, well, socialist, she watered it down with a promise that it would mean “stronger, happier and more productive workplaces”. What employer could object?

Stop complaining, in other words, open your chequebooks, and tell your members what they’re campaigning for

“And that’s still not all,” she said. Collective bargaining was coming back! “And there’s even more!” They were cheering her now. “Day one basic rights,” she was hammering her points home. “A ban on zero hour contracts. An end to fire and rehire. Family friendly working. Strengthen sick pay.” Our pens couldn’t keep up with the promises. It was starting to feel like the Christmas morning of an overindulged child, with bright goodies wondered at only for an instant before the next gleaming toy appeared.

There would be a price, of course, and Rayner turned to that next. “The battle for the general election is just getting started, and it’s not going to be easy,” she said. “We need your help and backing.” Stop complaining, in other words, open your chequebooks, and tell your members what they’re campaigning for.

It’s hardly the first time Labour has told union leaders what they want to hear. But when Jeremy Corbyn promised them a socialist paradise on earth, most of them were smart enough to know they would never see it. Underpinning every treat that Rayner promised was the thought that this might well happen. No wonder they hugged her when she finished.

Significant though the promises were, it’s important not to miss what else was happening. The deputy Labour leader was urging people to back the party without qualification or reservation, without a hint that if she were in charge, things would be better. And the leader had allowed her to make a speech full of popular promises, not insisting that he get to announce the really good stuff himself.

The relationship between Starmer and Rayner has been more strained than easy over the last three years, but the scent of victory is changing behaviour. For many in Labour over the past decade, it has often seemed that they were uncertain about whether it was better to be idealistic in opposition or to compromise in government. Rayner, at least, has worked out the answer.

Back in Westminster there was also the sense that the opposition is living its best life. Ed Miliband had put down a question about last week’s offshore wind auction, in which no one bid to build any more projects after a price was set that failed to account for inflation. Claire Coutinho, the new secretary of state, was sadly unavailable to answer, and so Graham Stuart, a junior minister, was sent in her place. It had all, he explained, been a triumph. “The auction delivered significant quantities of new solar and onshore wind generation,” he began, to Labour jeers. The episode had offered “valuable learning for subsequent auctions”.

On Miliband’s face, proper outrage at government failure had been battling with obvious delight at the situation. As the minister continued, there could only be one winner.

The auction, Stuart said, had been “highly successful” — Miliband slapped his thighs at that — the Labour argument was weak — Miliband hooted — the opposition wasn’t on the side of consumers — Miliband’s shoulders were shaking now — and the next auction would be “more successful still”. By now the entire Labour front bench was in stitches. Miliband raised his eyes upwards in pure joy. Winning at work indeed.