He came to level with the public about the predicament we are in, and the consequences for us all should President Donald Trump follow through on his threat to slap tariffs on the UK and take control of Greenland.
He left the audience in no doubt that we are facing the most serious crisis in the transatlantic relationship in decades, with huge uncertainty about what comes next.
Sir Keir Starmer was the most forthright I have seen him as he broke with President Trump, strongly criticising tariffs and insisting that on the matter of Greenland, the UK would not bend, whatever the consequences as he reminded the US that alliances were built on partnership, "not pressure".
But the prime minister also used this moment to try to de-escalate, as he stressed the importance of the US-UK relationship and dodged the matter of retaliatory tariffs in an effort to avoid any further poking of the bear.
It doesn't, by the way, mean the UK has ruled this option out - rather it is not a preferred solution and London would rather talk about other options. But the UK pointedly chose at this moment not to follow the EU by raising the prospect of retaliatory tariffs. That EU package, I'm told, could be released on Thursday.
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As I understand it, the prime minister is also "very unlikely" to attend Davos this week, given that there is no big set pieces on multilateral issues - be that Ukraine or Greenland, for now, that are likely to be resolved.
Instead, Keir Starmer will press on with his preferred method - talking intensely behind closed doors while saying as little as possible in public.
Danish minister reveals depth of rift
But if the prime minister doesn't want to reveal what is being said in private, the gravity of this rupture in the transatlantic alliance was laid bare by the Danish foreign minister and former prime minister, Lars Rasmussen - in London for talks with the foreign secretary - as he recounted the meeting he'd had with Vice President JD Vance and Secretary of State Marco Rubio in Washington last week.
"The meeting we had last week left me with the clear impression that the president, honestly and full-heartedly, wants to acquire Greenland. But we also made it crystal clear that this is a red line," he told me in an interview after his meeting with Yvette Cooper.
"We agreed to disagree. The concerns raised at the meeting and also in public, about security in the Arctic - [Trump's] concerns - we want to accommodate. Therefore, we agreed that we should move this dialogue from social media and Truth Social and other arenas into a meeting room where we could discuss whether there could be a solution building on what we already have agreed in the past."
Up for discussion was the US massively increasing its presence in Greenland, and the stepping up of NATO on the island, as well as guarantees stopping any presence of China in Greenland stretching out for 10, 20 or 30 years.
"I thought, we have managed not to solve the problem, but to find a pathway forward. It was disrupted by the statement from the president. And that's a reality of life," said Mr Rasmussen, as he spoke of his appreciation of the UK and other allies coming to stand by the Danes' side.
Bur what it also reveals is the depth of this transatlantic rift over Greenland.
Hours after the prime minister suggested he didn't think President Trump would send in troops to Greenland and called on the US to resolve these differences through dialogue, the US president told reporters he would impose 10% tariffs on the UK and other European countries that had sent troops to Greenland for a NATO exercise last week, and refused to rule out military force.
Europe's last hope to rein in Trump?
That we are in this situation a year into the Trump presidency is shocking and bewildering. For decades, the transatlantic alliance has framed our world order. Now that is being undone as President Trump exercises the law of power rather than working in the rule of law that has governed international relations since the Second World War.
Escalation in Greenland would rupture the NATO alliance should the leading member move directly into conflict with another partner, the Danes, who stood with the US after 9/11, suffering similar amounts of casualties to the US in Afghanistan.
It would trigger a trade war that would do all of us harm. It could result in the US withdrawing from Ukraine and embolden a Russian aggressor on the edge of Europe. The consequences are as unimaginable as they are serious.
But ultimately, President Trump knows he has the economic and military power to face down Europe, and it will take more than European diplomacy to persuade him to back down.
With the US president due at the annual World Economic Forum summit in Davos on Wednesday, huge attention will be paid to what he has to say in Switzerland - but it will be back in Washington where the difference might be made, as Mr Trump draws fire back home from Republicans in Congress.
If the Europeans can't rein him in, will his domestic lawmakers?
Republican House Speaker Mike Johnson met with Sir Keir in London on Monday, with the prime minister reiterating his position on Greenland and tariffs.
The best hope the Europeans have is to persuade Congress to act. The transatlantic relationship is, after all, bigger and more enduring than one man.
Nicha Rowson, who lives just metres from a major illegal waste site in Bickershaw, Wigan, said the 17-month ordeal has "teared our family apart".
The smell of the dump makes Nicha's son Oliver, who has autism, so physically ill that he moved out to live with his grandmother.
"It's put stress on our family, our mental health isn't great. It's like being separated parents. Even though me and my partner are together, we're sharing the child with the grandparents," Nicha said.
"I can't keep saying, 'oh soon it'll be cleared up' because it isn't. I don't know what else I can tell my child, why he has to live in this prison. Because it is, it's like a prison."
The family home has had such a major rat infestation that the family were forced to tear down their ceiling to tackle the issue. Nicha also found a dead rat in her living room.
"We could see rats running along our fences, running around the street at the front, they were just everywhere."
Nicha said she feels like she's "failing" as a parent. "I'm fighting and fighting, and I'm not winning the battle. At the end of the day if my child has to move out to be healthy, then that's what he has to do. But it's hard."
The dumping started on Bolton House Road in the autumn of 2024, and within a few months, mountains of waste formed in the quiet scrapyard.
Read more: Rats, flies and maggots plague Wigan residents
In July of last year, in the middle of a heatwave, a major incident was declared when the tip caught fire, forcing the local primary school to close for several days, and several residents were sent to hospital.
The fire burned for nine days, which caused such a strain on resources that residents had no water for days.
Nicha feels abandoned by the Environment Agency (EA) and the local council.
"All the way through we've been begging for help, we've done the professional emails but in the end we've resorted to saying this is inhumane, we're living in a prison, we need some help, and they're just ignoring us," she said.
Some 200 miles away, a similarly sized site in Kidlington, Oxfordshire made headlines before Christmas, with dumping starting there last summer.
But the EA has said it will spend £9.6m clearing the site in what they say is an "exceptional decision", leading the local MP Josh Simons to accuse it of seeming to apply "exceptional circumstances to middle-class areas in Oxford but not working-class towns in Wigan".
"When primary school kids are inhaling flames from a dump that's on fire, declared as a major incident, why does that not count as an exceptional circumstance?" he said in a post on X.
This divide was also raised in the House of Lords last week by Baroness Sheehan, the chair of the Lords' environment and climate change committee.
She told Sky News: "The nature of the waste in the Bickershaw site, it's hazardous waste, it is rotting waste. It really should be a high priority for the safety of the residents and the school children there."
Nicha says she feels like the authorities "don't care" about her and her husband's plight.
"We're working hard, we're both self-employed working six, seven days a week, and we've got to the point now where our house isn't worth anything, and no one gives a hoot - no one cares," she said.
"Because of the tip, the smells… it devalued our house [that] if we sold it, we might not get enough to cover the mortgage that's outstanding on it.
"My message to the Environment Agency is to stop thinking about the money and passing the buck - think about the mental and physical health of the residents."
What's being done about it?
A spokesperson for the EA told Sky News that they are paying to clear the Kidlington site due to "new information [that] has come to light about the rapidly escalating fire risks with potential to close the A34 major highway and impact key electrical supplies".
The spokesperson continued: "This does not undermine the real impacts to the local community in Wigan, and we are doing everything within our power to ensure that the perpetrators pay the price to clean up the site, rather than taxpayers."
Wigan Council is paying for a part of the site to be cleared where the waste has spilled onto a nature reserve that the council owns.
A spokesperson said this clear up "will come at a cost to the council" and that the council "understands the difficulties that residents living close to the illegal waste site at Bolton House Road have endured and would like to see the entire site cleared as a matter of priority".
"The leader of the council, David Molyneux MBE, has written to the chief executive of the Environment Agency to understand why funding was made available for the waste site in Oxfordshire, but not for Bolton House Road," the spokesperson has said.
"The council would like to call on the government to make funding available - via the Environment Agency or other department - as has been done for other sites, given the risks the site poses and the detrimental impact this has had on neighbouring residents and the adjacent primary school."
Nightmare situations such as taps running dry in Kent and Sussex recently would be avoided, the government says, thanks to a new proactive system that would perform "MOTs" on water companies to preempt major failures.
Ministers are set to unveil a series of reforms in parliament on Tuesday as they move ahead with a major shake-up in the industry in England and Wales, including abolishing the current system of overlapping regulators.
Public confidence in the old way collapsed as sewage spills grew and pipes crumbled, while water company bosses enjoyed ever bigger bonuses.
The new plans, outlined in a White Paper on Tuesday, would create one single regulator, as well as an ombudsman to make it easier for bill-payers to complain about their suppliers.
But campaigners and the water industry have warned the proposals won't come in soon or reach far enough.
'Nowhere to hide'
Environment Secretary Emma Reynolds called the proposals a "once-in-a-generation set of reforms" to tackle water pollution and "poor performance by water companies".
Under the government's proposals, water companies will have to perform health checks on their infrastructure to proactively identify problems with pipes or sewage treatment works before they fail.
A new chief engineer at the regulator will also bring back hands-on checks of infrastructure, something not seen for 20 years.
Ms Reynolds told Sky News: "We're going to move away from a system whereby water companies mark their own homework to having a new regulator - abolishing Ofwat - with more teeth, so that there'll be nowhere to hide for poor performance."
Change 'desperately needed'
It comes as complaints to the consumer body, the Consumer Council for Water, rose 50% in the last year while trust hit an "all-time low".
Its chief executive Mike Keil said: "The miserable disruption inflicted on people in parts of Sussex and Kent in recent weeks underlines why meaningful change in the way water companies are regulated and treat their customers is desperately needed."
He welcomed the proposed new ombudsman, which would have legal powers to resolve disputes and force water companies to compensate for issues.
Government urged to tackle 'root cause of crisis'
The planned changes come as part of the government's response to public fury over rising bills, sewage pollution and large payouts for executives.
Last year it commissioned an independent review that made 88 recommendations to repair one of the world's only fully privatised water systems.
But it ruled out re-nationalisation of the water industry, which it sees as too expensive and disruptive, but which some campaigners say is the only solution.
James Wallace, CEO of River Action, said the government "recognises the scale of the freshwater emergency, but lacks the urgency and bold reform to tackle it".
He said none of the proposals would "make a meaningful difference" without tackling privatisation, which is the "root cause of this crisis".
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Water companies also warned the changes might come in too slowly. The government expects them before the next general election, but can't yet put a date on it.
A spokesperson for the industry body Water UK said: "We cannot afford for any more long-term decisions to be taken by a system everyone knows has failed.
"The need for major reform has long since been agreed. Delivery now needs to catch up."
The proposals so far were also light on reforms to other sectors that pollute Britain's waterways, such as farms, housing, and roads - though more detail is expected in the White Paper on Tuesday.
"Crimes on our streets are going unpunished" and are "plaguing communities", a senior source warned, as the government prepares to announce significant reforms to policing this month.
Home Office figures shared with Sky News show the number of trained uniformed police officers in back-office roles like HR and IT support has surged by 40% in the past six years to more than 12,600.
Meanwhile, the number of visible frontline officers has fallen to around 67,000, down from more than 70,000 a decade ago.
Government sources blamed "arbitrary" headcount targets, which they suggest incentivise hiring officers to desk jobs.
The Officer Maintenance Grant, introduced under Boris Johnson's government, is expected to be scrapped and replaced with protected funding for neighbourhood officers.
It comes as the Metropolitan Police Commissioner Sir Mark Rowley has called for a dramatic overhaul of the policing system as he said the current model is "out of date".
Speaking to Sky's Trevor Phillips, Sir Mark said he believed there should be a reduction in the 43 police forces across England and Wales as a shake-up of the system is "overdue".
Shoplifting top of public concern
Internal Home Office polling, shared with Sky News, found that shoplifting is the crime people worry about most, along with anti-social behaviour, including concerns about drugs and knife crime.
Shop theft has risen by 72% since 2010 and reached record levels in the year ending March 2025, with fewer than one in five incidents resulting in a charge.
A government source admitted many town centres feel "abandoned" as officers are "increasingly burdened by bureaucracy and stuck behind desks instead of out on the frontline".
They said "criminals feel they can cause havoc on our streets with impunity".
'A reactive service'
The government has pledged 13,000 more neighbourhood officers by the end of the parliament and has committed to a record £18.4bn police funding settlement announced last week.
Policing has become a "reactive service focused on crisis response, rather than fighting crime", a government source said.
At least 40 people were killed and 159 injured in a high-speed collision between two trains on Sunday.
Here, the Sky News Data & Forensics team looks at how the crash unfolded.
A timeline of the crash
Before the crash, a train run by private company Iryo and carrying around 300 passengers departed from Malaga on a journey to the capital Madrid at 6.40pm (5.40pm GMT).
The other train, which was carrying nearly 200 people and managed by Spain's public train company Renfe, departed Madrid for Huelva in the south at 6.05pm local time (5.05pm GMT).
Around 7.45pm local time (6.45pm GMT), the tail end of the first train travelling from Malaga to Madrid derailed and jumped onto the opposite side of the tracks.
It then crashed into the other train near the town of Adamuz in the province of Cordoba, around 230 miles south of Madrid.
At the time of the crash, both trains were travelling at more than 120mph.
Footage showed passengers climbing out of smashed windows after the crash, with emergency services on the scene.
The injured were taken to a nearby hospital.
'A truly strange' incident
Spain's transport minister Oscar Puente said the cause of the crash was unknown, but called it "a truly strange" incident because it happened on a flat stretch of track that had been renovated in May.
He said the back of the Iryo train had derailed and then veered across the other track, slamming into the front of the Renfe train and knocking its first two carriages off the track and down a four-metre slope.
The worst damage was to the front section of the Renfe train, he added.
Mr Puente shared a picture showing the system used to monitor the infrastructure and movement of all trains along the network.
The map showed the live positions of the two trains just under two hours after the crash happened, with red lines indicating the track was blocked.
Investigators say faulty joint could be key to crash
An initial investigation has identified a faulty joint as key to the train crash, Reuters reported, citing a source.
The news agency said technicians identified some wear on the joint between sections of the rail, known as a fishplate, which they said showed the fault had been there for some time.
Ian Prosser, former HM chief inspector of railways, said the derailment was most likely due to a track issue, such as a broken rail.
"The most likely case would be a track fault of some sort or something went wrong with the train," he said. "But that would be very rare."
High-speed train crashes on straight rail lines, as happened in this case, are also rare, Mr Prosser said.
"It takes quite a long time for a train to actually come and sort of stop," he added. "So at that speed would be travelling for quite some time after the actual initial impact."
Human error 'ruled out'
Earlier, the president of Spain's national railway company Renfe, Alvaro Fernandez Heredia, had said "human error could be ruled out".
The Iryo train had been built in 2022, with its last inspection carried out on 15 January this year.
The track the crash occurred on was also new, having been completely renovated last May, with an investment of €700m (£607m).
However, it still had issues, with a Spanish train drivers' union warning rail operator Adif of the heavy wear and tear on the tracks, including the one where the two trains collided, in a letter last August.
In October last year, rail unions approached the government to request a reduction of speed to avoid accidents on the line.
Spain's rail safety record
Spain's railway safety agency (AESF) has recorded between 42 and 98 significant rail accidents per year since 2006, with the most accidents in 2007 and 2023, at 98 and 77 respectively.
Those years saw a particularly high number of level crossing and personal injury accidents, with the agency highlighting the notably lower figure for 2024, at 57 compared with 77, was mainly due to a reduction in those types of incidents rather than in collisions and derailments.
In 2024, one in five incidents in Spain were caused by derailment - five times the EU average of 4%, with the country recording a smaller proportion of level crossings and other personal injury incidents than the EU average.
Some 18 people were killed in railway accidents in Spain in 2024, the equivalent of around one person per 1,000km of railway tracks, leaving Spain among the countries with the lowest level of rail fatalities in the EU, according to the European Commission.
The worst Spanish railway accident this century was a train derailment in Santiago de Compostela in July 2013, which killed 79 people.
Prosecutors set to open criminal probe as soon as possible
Sources from Spain's interior ministry told Sky News local prosecutors are waiting for the report from police, and are then set to open a criminal probe as soon as possible.
Asked by reporters how long an inquiry into the crash's cause could take, the transport minister Mr Puente said it could be a month.
Spain's Prime Minister Pedro Sanchez expressed his condolences to the victims' families in a post on X, writing: "Tonight is a night of deep pain for our country."
On Monday night, as many of the injured left hospital, some family members were still scouring social media and hospitals for more information about their missing loved ones.
The Data x Forensics team is a multi-skilled unit dedicated to providing transparent journalism from Sky News. We gather, analyse and visualise data to tell data-driven stories. We combine traditional reporting skills with advanced analysis of satellite images, social media and other open source information. Through multimedia storytelling we aim to better explain the world while also showing how our journalism is done.