The day after Sir Keir Starmer said he wanted Angela Rayner back in the cabinet, she showed Labour MPs what they’ve been missing.

The former deputy prime minister delighted Labour backbenchers with a powerful Commons speech defending her workers’ rights legislation on Monday evening.

With the House of Lords locked in a battle of parliamentary “ping pong” with MPs, she told ministers: “Now is not the time to blink or buckle.”

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Her very public intervention came amid claims that her next move has the Labour Party on tenterhooks and that she’s the favourite to succeed Sir Keir if she wants the job.

And her speech, delivered from notes and clearly meticulously prepared, appeared to send a message to Labour MPs: I’m here to make a comeback.

The government’s flagship Employment Rights Bill was championed by Ms Rayner when she was deputy PM, in the face of bitter opposition from the Conservatives.

In a bid to end the deadlock with the Lords, ministers have backed down on unfair dismissal protection from day one, proposing a compromise of six months.

Backing the compromise, brokered with the TUC, Ms Rayner said: “I know ministers had faced difficult decisions and difficult discussions with the employers and worker representatives.

“But I strongly believe that the work that has been done has been necessary, and we should be able to move forward now.”

Attacking the upper chamber for delaying the legislation, she said: “There is now no more time to waste.

“Vested interests worked with the Tories and the Lib Dems and, cheered on by Reform and backed by the Greens, to resist the manifesto on which we were elected.

“And now there can be no excuses. We have a mandate for a new deal for working people, and we must, and we will deliver it.

And she concluded: “It has been a battle to pass this bill, but progress is always a struggle that we fought for. Its passage will be a historic achievement for this Labour government.

“It will benefit working people now and into the future. Now is not the time to blink or buckle. Let’s not waste a minute more. It’s time to deliver.”

It was the sort of fighting talk and defiance of the government’s opponents that will have cheered up Labour MPs and boosted her hopes of a comeback and even a leadership bid.

It came as speculation over Sir Keir’s future grows more frenzied by the day, with claims that even some of his own supporters have begun the hunt for his successor.

The thinktank that ran his leadership campaign in 2020, Labour Together, is reported to be canvassing party members on candidates to replace him.

There was even a claim last week that allies of Wes Streeting were sounding out Labour MPs about a pact with Ms Rayner and a joint ticket for the leadership.

The health secretary dismissed that claim as a “silly season story”, while a Rayner ally said: “There’s no vacancy and there’s no pact”. They added that she will not “be played like a pawn”.

Mr Streeting did, however, start speculation himself when he said in his Labour conference speech: “We want her back. We need her back.”

Fuelling more speculation, Sir Keir went further than he had previously on Sunday, when he was asked in an Observer interview if he missed her and replied; “Yes, of course I do. I was really sad that we lost her.”

And asked if she would return to the cabinet, the prime minister said: “Yes. She’s hugely talented.”

Sir Keir also described Ms Rayner, who left school at 16 without any qualifications, as “the best social mobility story this country has ever seen”.

But a swift return to the cabinet would be hugely controversial, because the PM’s ethic adviser, Sir Laurie Magner, ruled that she breached the ministerial code by underpaying stamp duty when she bought a flat.

But she has been linked to speculation about possible efforts to remove Sir Keir if – as predicted – Labour performs badly in the Scottish, Welsh and local elections next May.

Her supporters also claim she will eventually be cleared by HMRC over her stamp duty breach, clearing the way for her to come back.

And her latest speech – combative, defiant and yet loyal – will have boosted her hopes, and reminded Labour MPs what they’ve missed since she quit in September.

The Sandie Peggie case has been such a high-profile story because it gets to the heart of the debate about trans rights versus women’s rights, which has been so fraught in recent years – especially in Scotland.

While the Supreme Court ruled in April that the Equality Act referred to a person’s biological sex – with major ramifications over who can use female-protected spaces – we are still waiting for long-delayed government guidance on how this should be applied. We are told it’s due “as soon as possible”.

Government minister Dame Diana Johnson brightly told Darren McCaffrey on Sky’s Politics Hub on Monday that organisations “just need to get on with it – the law is clear”.

But with so many organisations waiting for government guidance before changing policy – that’s clearly not the case.

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Campaigners have criticised the Peggie tribunal for not following the Supreme Court’s lead more directly. The tribunal didn’t find that it was wrong to let Dr Upton use the female changing rooms – just that action should have been taken after Ms Peggie complained.

Her lawyers say that is hugely problematic, as it puts the onus on a woman to complain.

The political reaction has been swift. Conservative leader Kemi Badenoch has long been outspoken on this issue, and she has posted a typically punchy statement in response to the case.

“It’s ridiculous it took two years to reach a verdict that was so obvious from the start,” she wrote on X.

“This entire episode is indicative of a system wasting time and taxpayers’ money to please a small cabal of activists.”

But it’s not just the Tories. Scottish Labour MP Joani Reid described Ms Peggie’s treatment as “a disgrace…enabled by a warped NHS culture and fostered by a Scottish government that refused to listen to women’s concerns”.

Of course, the SNP have always been hugely supportive of trans rights, attempting to pass gender recognition laws which would have made it much easier for people to self-ID. That legislation was blocked by the UK Supreme Court.

John Swinney gave a carefully worded response when asked about the issue on Monday, saying “it’s important to take time to consider the judgment” with no further comment on the questions raised by the case.

Sir Keir Starmer, too, has long been dogged by criticism over the lack of clarity in some of his answers to the question “what is a woman”, although he has sought to be more definite in recent years.

Anna Turley, the chair of the Labour Party, said on Monday that it’s more important to get the Supreme Court guidance right than to get it out quickly.

But Monday’s judgment shows the urgent importance of both.

With Do Kwon scheduled to be sentenced on Thursday after pleading guilty to two felony counts, a US federal judge is asking prosecutors and defense attorneys about the Terraform Labs co-founder’s legal troubles in his native country, South Korea, and Montenegro.

In a Monday filing in the US District Court for the Southern District of New York, Judge Paul Engelmayer asked Kwon’s lawyers and attorneys representing the US government about the charges and “maximum and minimum sentences” the Terraform co-founder could face in South Korea, where he is expected to be extradited after potentially serving prison time in the United States.

Kwon pleaded guilty to two counts of wire fraud and conspiracy to defraud in August and is scheduled to be sentenced by Engelmayer on Thursday.

In addition to the judge’s questions on Kwon potentially serving time in South Korea, he asked whether there was agreement that “none of Mr. Kwon’s time in custody in Montenegro” — where he served a four-month sentence for using falsified travel documents and fought extradition to the US for more than a year — would be credited to any potential US sentence.

Judge Engelmayer’s questions signaled concerns that, should the US grant extradition to South Korea to serve “the back half of his sentence,” the country’s authorities could release him early. 

Kwon was one of the most prominent figures in the crypto and blockchain industry in 2022 before the collapse of the Terra ecosystem, which many experts agree contributed to a market crash that resulted in several companies declaring bankruptcy and significant losses to investors.

Defense attorneys requested that Kwon serve no more than five years in the US, while prosecutors are pushing for at least 12 years.

Related: There’s more to crypto crime than meets the eye: What you need to know

The sentencing recommendation from the US government said that Kwon had “caused losses that eclipsed those caused” by former FTX CEO Sam Bankman-Fried, former Celsius CEO Alex Mashinsky and OneCoin’s Karl Sebastian Greenwood combined. All three men are serving multi-year sentences in federal prison.

Will Do Kwon serve time in South Korea?

The Terraform co-founder’s lawyers said that even if Engelmayer were to sentence Kwon to time served, he would “immediately reenter pretrial detention pending his criminal charges in South Korea,” and potentially face up to 40 years in the country, where he holds citizenship. 

Thursday’s sentencing hearing could mark the beginning of the end of Kwon’s chapter in the 2022 collapse of Terraform. His whereabouts amid the crypto market downturn were not publicly known until he was arrested in Montenegro and held in custody to await extradition to the US, where he was indicted in March 2023 for his role at Terraform.