During the programme, former Cabinet Secretary Lord Case said that leadership uncertainty "costs us opportunities".

He points to issues around defence spending, which he says is a "huge issue" with enormous national and international significance, and also "political significance" - pointing to the resignation of former Defence Secretary John Healey.

• For context: Healey stepped down last week citing concerns a yet-to-be-published defence investment plan failed to deliver on the UK's defence needs "at this dangerous time"

Case also says that a further change in leadership is likely to generate "a high degree of eye-rolling", costing the UK "influence on the world stage".

Also in the Sunday with Laura Kuenssberg hot seat is shadow chancellor Mel Stride, who says he doesn't think the Conservatives are responsible for the current political system of successive changes in PMs.

He adds that we need "stability" at all times in our political system as well as the right policies.

Stride says there's no evidence Andy Burnham is in the position to change the "fundamental nature" of the Labour Party in Parliament - claiming that Burnham "flip flops" and "doesn't seem to know what the fiscal rules are".

He notes the Tories' success in the Aberdeen South by-election this week, saying it was based on the party's policies on energy and North Sea oil and gas.

The shadow chancellor also says his party is becoming "increasingly competitive", adding that Reform lost the Makerfield by-election despite throwing the "kitchen sink" at it and describes Nigel Farage's party as "fantasy economists".

• The programme has now concluded but stay with us as we bring you more on the latest political developments and analysis.

Kuenssberg next sits down with former Keir Starmer adviser Paul Ovenden, asking how the PM is likely to be feeling right now.

Ovenden says that Starmer's way of thinking was always: "Put the country first, the Labour Party second, and probably his own ambitions or well-being third." He says this is what will "guide his way of thinking" now.

Reflecting on Starmer's leadership in the 2024 General Election, he says the PM has earned the respect to make whatever decision he will make "in his own way and his own time".

Kuenssberg turns to Andy Burnham, who Ovenden says has "fantastic charisma" and is able to connect with voters.

He says as long as the 2024 manifesto is "honoured in spirit", there shouldn't be a problem in someone elected in a by-election potentially taking on the party leadership.

Nick Eardley
Political correspondent

The firm - perhaps overwhelming - favourite to be the next prime minister is Andy Burnham.

But what will he do with power, if he gets it?

On Laura Kuenssberg's panel, Labour MP Toby Perkins asks: "We do need to know if we've got a change of direction, are we basically still supporting the manifesto we were all elected on?"

Luke Charters, another Labour MP supporting Andy Burnham, insists the answer is yes - but the current leadership has been too timid.

Kuenssberg turns to her panel to discuss the interviews with her guests.

Starmer supporter Toby Perkins says the government is delivering on the main things that it said it would do, and that we could do with "calm heads".

Asked whether it was "serious" for some of Labour to be trying to get rid of an PM in office, Burnham backer Luke Charters says the country is in a "vastly different" now than it was when Labour won the 2024 General Election in a landslide victory.

Jess Phillips weighs in, saying Andy Burnham will have to "prove that is that unifier" that Charters claims he is, beyond Makerfield and Greater Manchester.

She says it looks like a "slow resignation" is taking place after Peter Kyle's interview.

Kyle made it clear Starmer is weighing up his futurepublished at 09:38 BST

09:38 BST

Nick Eardley
Political correspondent

The signs the prime minister is considering resigning are clear from what we've heard this morning.

The business secretary said he did not know for sure what was about to happen.

But he was also clear Keir Starmer is weighing up his future - reflecting on political reality and the challenges he faces.

The prime minister, Peter Kyle said, will do "what is in the best interests of the country".

A growing number of figures in government believe the prime minister is preparing to set out plans for his departure as soon as Monday.

Number Ten continues to point to the PM's words on Friday, when he said he intended to fight and leadership challenge.

Kuenssberg has been speaking with former Defence Secretary Lord Hutton, who says there is a "high chance" that Keir Starmer is on his way out.

He adds that he wants any transition to be done in the "best possible way" and to put the country's interests first.

Hutton says that Burnham has to know where he wants to take the country and be "clear in his mind" about how to address the fundamental challenges it faces.

"I think there's a challenge, for sure," he says. "And I think it must be met and mastered by Andy and any of the other candidates who want to put their hat in the ring.

"We've got to get a sense of where they want to take the country. And I think that's the very least that leadership candidates owe to the electorate at this moment in time. The country is watching."

Hutton says that the Labour Party has a mandate based on the 2024 election that it should stick to, adding he has nothing but respect for Burnham as a leader and he has all the necessary skills "in abundance".

Kyle is then asked if Andy Burnham has the qualifications to lead Labour, to which he says the party is "burgeoning" with talent.

He adds that Burnham "could be one of those people", and that the business secretary would grab the opportunity to serve in any Labour cabinet "with both hands".

Kuenssberg puts to Kyle that Labour is entering some form of "transition", to which he says he doesn't want to appear "delusional" that the prime minister is not being challenged.

He says what is important is that "we govern through whatever unfolds or may not unfold in the days ahead", adding that potential challengers also want this to be the case.

Kuenssberg asks if this means an "orderly transition". Kyle says no, and repeats that the country must be put first.

She notes that is a "world away" from what the PM is saying about fighting any leadership challenge. Kyle responds: "The reality right now is that there is process under way, there are people who seek to challenge Keir." He adds that he doesn't know "for fact" what the next few days will entail.

Any change that may or may not happen should be done in a "functional way", he says, and Labour needs to learn from the Tories - including in understanding that it is not true that when a problem arises, "changing the person at the top would fix everything".

The leadership is "more than one person", he says and all of Labour needs to "bear responsibility" for the failures.

Asked whether there should be a contest, he refuses to answer but says in his view contests are always better.

Kyle says he had a "thoughtful" conversation with the prime minister on Friday, but declines to say what was discussed as it was "private".

The business secretary adds there is clearly "political uncertainty" at the moment and that Starmer has had several conversations with union leaders, among others.

Kyle says Starmer is currently exercising his job with "authority", pointing out the India trade deal negotiation and implementation at the G7 this week, and adding that he himself wants to do his part to ensure his authority "through this period".

Nick Eardley
Political correspondent

The tone from Government has changed this morning.

Peter Kyle is not repeating the prime minister's insistence from Friday - that he would stay on and contest a leadership election.

Kyle says the prime minister was spending the weekend considering the political challenges he faces.

He says the prime minister will be framing his decision based on "what's in the best interests of the country".

Amid heightening speculation in Government that the prime minister is going to stand down - the business secretary is not repeating the often made argument that Sir Keir Starmer plans to fight on.

Peter Kyle says Starmer is making time this weekend to reflect on the political realities today, compared to last week and the week before.

It will always be about the best interests of the country, he says

Labour's leadership struggles are the focus of Sunday's papers. Keir Starmer could announce his departure date as early as tomorrow, a Labour MP has told the Telegraph.

Starmer is expected to resign on Monday, the Observer headlines on. According to the paper, the prime minister "accepts his position is no longer tenable".

Meanwhile, the Sunday Mirror headlines on the "historic royal move" by King Charles in releasing his personal tax return - Britain's first monarch to do so in modern times.

It is 09:00 BST, meaning Sunday with Laura Kuenssberg is starting now.

On today's programme:

• Business Secretary Peter Kyle
• Shadow chancellor Mel Stride
• Former adviser to Keir Starmer, Paul Ovenden
• Former Cabinet Secretary Lord Case
• Former Defence Secretary Lord Hutton

The show's panel will also be giving their insights, with Labour MPs Jess Phillips, Toby Perkins and Luke Charters joining.

We will be bringing you text updates from the programme over the next hour and you can also watch live at the top of this page.

Keir Starmer has been making time this weekend to "reflect on the political realities" that he finds himself in, the business secretary says.

Peter Kyle tells Sky News' Trevor Phillips that he had a "frank" conversation with the prime minister on Friday.

He says that both of them have been reflecting in their own ways about what "putting country first" means in the current moment.

Kyle adds: "He is, as well as working really hard over this weekend, I think he is making time to reflect on the political realities, challenges and opportunities that he finds himself in."

We will shortly be hearing from the business secretary on Sunday with Laura Kuenssberg, which you can watch live at the top of this page from 09:00.

Image source, EPA/Shutterstock

• Calls for Keir Starmer to set a timetable for his resignation have escalated after Andy Burnham led Labour to victory in Thursday’s Makerfield by-election, a win which the newly elected MP said was an "opportunity to turn the tide… make the country feel like it's working again"

• Elsewhere, the Scottish Conservatives won their first Westminster by-election in more than 50 years in Aberdeen South, while the SNP retained Arbroath and Broughty Ferry by over 5,000 votes

• Under-16s in the UK will be banned from using social media by spring next year, Starmer announced, following a government consultation in which 89% of 9,499 parents and carers said they strongly supported a legal minimum age for social media access
• Starmer also attended France's G7 summit this week, saying that the UK will play its "full part" in getting the Strait of Hormuz reopened "as soon as possible", before Iran said on Saturday it had closed the waterway ahead of fresh talks with the US
• The government's proscription of Palestine Action as a terror organisation is lawful, the Court of Appeal has ruled, overturning an earlier decision from the High Court that the ban had breached the right to protest and had been incorrectly taken by ministers
• Green Party leader Zack Polanski has been cleared by the Greater London Authority following a complaint over his failure to pay council tax on a houseboat in Hackney, with a monitoring officer saying that "no further action" was needed and the case had been closed

Image source, Reuters

Keir Starmer has been adamant that he is "not going to walk away" from his role as prime minister. And No 10 this morning says he's getting on with the job.

However, should his position change, Starmer could choose to stay in post during a transition period before handing over to a successor, who would be both Labour leader and prime minister.

If Starmer chose to resign with immediate effect, a member of the cabinet would replace him in a caretaker capacity.

This would involve a decision by the cabinet, which would consult with Labour's National Executive Committee. Deputy Prime Minister David Lammy would not necessarily fill the caretaker role.

A leadership contest would then follow.

In this scenario, each potential challenger would need support from 20% of the party's MPs and to be backed by either 5% of constituency Labour parties, or at least three affiliated organisations - of which two must be affiliated trade unions.

Laura Kuenssberg
Presenter, Sunday with Laura Kuenssberg

Image source, Reuters

"We promised people we weren't going to do this."

There is exasperation in the voice of a long time Labour adviser. But as every hour passes, it is more likely the UK will soon have its seventh prime minister in 10 years.

Talk of Sir Keir Starmer fighting is fading, his exit seems more likely as the weekend goes on. The prime minister is at his country retreat, Chequers, spending time with his wife.

The man coming for his job, Andy Burnham, is spending the weekend with his family, away from home too.

Several sources told me Starmer really does believe he could beat Burnham in a leadership contest, and concluded that a fortnight ago after watching him on BBC Question Time on a Thursday, then failing to explain the borrowing and spending rules in a Newsnight interview on the Friday.

A government insider said: "On Saturday he phoned his closest allies and said, 'I'm sure I could win'."

But the widespread assumption this weekend in the party is that Burnham would beat him hands down, and another government source said "it's nuts" to imagine the PM could come out on top.

An increasing number of ministers, previously loyal to Starmer, now think it's time as one cabinet source told me they "wouldn't want the prime minister to humiliate himself" in a race.

The chances of him staying to fight are diminishing. But what is still a mystery this weekend is exactly how Starmer will respond.

• Read more: Talk of Starmer staying on to fight is fading - fast

Leadership uncertainty is "enormously disruptive" and presents a "big challenge" for the government, a former cabinet secretary has said.

Simon Case, the UK's highest-ranking civil servant from 2020 to 2024, tells the BBC's Sunday with Laura Kuenssberg that political upheaval also "costs us money" by driving up borrowing costs.

His comments come after Andy Burnham won Thursday's Makerfield by-election, paving the way for a Labour leadership challenge.

Prime Minister Sir Keir Starmer is now under pressure from cabinet ministers and a growing number of MPs to set out a plan for his departure, and avoid the need for a leadership contest.

• Read the full story

As we've just reported, No 10 is steadfast in its message: Starmer is getting on with the job.

Downing Street's reiteration of the PM's position follows reporting in The Observer that Starmer is expected to resign on Monday and set out an orderly exit.

The news outlet cites a source as saying: "He’s come up hard against the reality that the support isn’t there... the truth is everyone knows this is no longer a tenable proposition. There’s a sadness about it all, of course, but sometimes there’s just an inevitability in politics and as Boris Johnson said, 'When the herd moves it moves'."

It adds senior Labour figures believe a “clear statement” could come as early as Monday.

The BBC has not independently verified the reports.