Rishi Sunak has been confronted over the tragic death of a 26-year-old cancer patient whose mum called an ambulance which didn't show up.
At a tense PMQs session, Labour leader Keir Starmer demanded the rattled PM apologise for the "lethal chaos under his watch" in the NHS.
Alarming new figures show that 37,000 people with 'emergency' conditions such as heart attacks and strokes waited more than three-and-a-half hours for an ambulance to arrive last month.
The Labour leader accused Mr Sunak of attempting to deflect blame as critically ill patients face lethal waits for paramedics.
MPs fell silent as Mr Starmer told the House of Commons: "Stephanie from Plymouth was battling cancer when she collapsed at home. Her mum rang 999 desperate for help.
"She only lived a couple of miles from the hospital but they couldn't prioritise her. She was 26 when she died waiting for that ambulance, a young woman whose life was ended far too soon. As a dad I can't even fathom that pain."
He continued: "On behalf of Stephanie and her family, will he (Mr Sunak) stop the excuses, stop shifting the blame, stop the political games and simply tell us when will he sort out these delays?"
The opposition leader further demanded: "If he won't answer any questions, will he at least apologise for the lethal chaos under his watch?"
Mr Sunak described Stephanie's death as a tragedy - before accusing his opponent of "playing political games".
He said: "Of course Stephanie's case is a tragedy. Of course people are working as hard as they can to make sure people get the care they need.
"But he talks about political games - he is a living example of playing political games when it comes to people's healthcare.
"I've already mentioned what's been going on in Wales. Is he confident in the Labour-run Wales NHS that nobody is suffering right now? Of course they are because the NHS everywhere is under pressure."
Mr Sunak continued: "But I'll ask him this: if he is so concerned about making sure that the Stephanies of the future get the care they need, why is he denying those families the guarantee of emergency life-saving care?"
Sir Keir responded: "So that's his answer to Stephanie's family? Deflect, blame others, never take responsibility.Mr Starmer said that in some parts of the country, people who call for an ambulance are being forced to wait more than two-and-a-half hours on average - despite a target of 18 minutes.
He told MPs that if someone in Peterborough called an ambulance at midday, it would not arrive until 2.10pm - while in Northampton it would take until 2.20pm, and in Plymouth medics would not arrive until 2.40pm on average.
Mr Starmer asked the PM: "It's three minutes past 12. If somebody phones 999 now because they have chest pains and fear it might be a heart attack, when would the Prime Minister expect an ambulance to arrive?"
The PM replied: "It's absolutely right that people can rely on the emergency services when they need them.
"That's why we are rapidly implementing measures to improve the delivery of ambulance times and, indeed, urgent and emergency care, but I'd say to the honourable gentleman, if he cares about ensuring that patients get access to life-saving emergency care when they need it, why won't he support our minimum safety legislation?"
In a statement released during the confrontation, Labour said 37,000 people with “emergency” conditions - such as suspected strokes or heart attacks - waited more than three hours and 40 minutes for an ambulance last month.
Shadow Health Secretary Wes Streeting said: “Patients can no longer rely on the NHS being there for them in an emergency. Heart attack and stroke victims are left waiting hours for an ambulance, when every second counts.
“That is the terrifying reality after 13 years of Conservative mismanagement of the health service."
Following the PMQs confrontation, Tory MP Johnny Mercer, who represents Plymouth, posted on Twitter: "Keir Starmer has made a serious allegation to the Prime Minister in the House that a 26 year old constituent of mine has tragically died because of a failure in the Ambulance service in our City.
" I am urgently investigating and will report back."
Both party leaders voiced their horror over the conviction of rapist police officer David Carrick, who admitted 48 rapes.
"The police must address the failings in this case," said Mr Sunak.
The Prime Minister faces a multitude of problems as he tries to push through controversial anti-strike legislation.
Today thousands of nurses at 55 NHS trusts across England are taking part in a walkout in a long-running dispute over pay and conditions.
Tory MP Simon Clarke was today branded "out of touch" after claiming nurses who use foodbanks that they need to "budget better and take responsibility."
The government's minimum service proposals have been blasted by the chief of the United Nations workers' rights agency.
International Labour Organisation (ILO) director general Gilbert Houngbo said he was "very worried" that workers may be forced to "accept a situation that's below par".
Mr Sunak and his ministers had previously suggested the UN agency supports the kind of "minimum service levels" legislation he is pushing through Parliament.
But Mr Houngbo and US labour secretary Marty Walsh both raised concerns with the BBC at the World Economic Forum in Davos.
Mr Houngbo said he did not want to interfere in national discussions but stressed the need for "social dialogue" between workers and bosses, particularly during the current economic downturn.
"We're very worried that workers may have to accept a situation so they don't have to get themselves out of a job. They may have to accept a situation that's below par," he added.
He said the ILO "has been in discussions" with British trade unions over whether they may file a complaint to assess whether the UK is breaching international worker rights laws
The BBC reported that Mr Walsh asked the broadcaster to put the same question to him, about supporting the minimum service agreements, after hearing the conversation.
Mr Walsh, a former union official, replied: "No. I don't know about the legislation. But I certainly will work with the ILO.
"I would not support anything that would take away from workers."
