Problems with social care are “clogging up” hospitals, adding to an “existential” crisis for the NHS, Wes Streeting has said.

But the Health Secretary indicated fundamental reform of the social care system – and the crucial issue of how to pay for it – would have to wait until the second term of a Labour government.

Mr Streeting said his immediate priority was stabilising the social care service and making sure it was working properly with the NHS.

“The challenge we’ve got in health and social care is enormous. It’s the worst crisis in the history of the National Health Service,” he told a Labour conference fringe event in Liverpool.

“The Darzi investigation laid out in evidence, data-driven terms the scale of the challenge and the scale of the failure.

“And it is a paradox about the NHS, in a way: every single day, there are brilliant people that deliver outstanding care right throughout the NHS, and yet we are in a position where, if you’re a cancer patient, your outcomes are far more likely to be worse than if you live in other comparable countries, where people struggle to access a GP, where if you call an ambulance you can’t be certain it will arrive on time.

“It is a grave crisis, and it is existential, not just because of the scale of the crisis today, but the existential risk of the NHS in the long term, unless we take the right long-term reform decisions, to make the NHS sustainable and fit for the future.”

There was also a “a real crisis in social care”, he said, adding: “I think people in this country are genuinely shocked when they need social care to find out how expensive it is and how poor the quality of social care is.”

Fixing the social care system was also “mission critical” for the NHS, he said, “because so many of the challenges that are presenting either at the NHS’s front door or clogging up the exit doors of hospitals – so many of those things are driven by social care”.

Under a 10-year plan, the first five years would involve “stabilising the system and making sure it’s got the workforce that it needs to deliver”, with “clear and consistent” national standards, making sure the relationship between the NHS and social care was in a “good enough” place to avoid putting extra pressure on the health service.

“I think those are reasonable goals for the first term of a Labour government. But we’ve also got to think across the 10-year horizon. How do we make sure that social care is fit for the changing needs of the 21st century?

“And I think this is where this needs to be much more of a national conversation, because we’ve got to have an honest conversation with the country about what we want from social care, how we would like to pay for what we want from social care and then how the system is constructed to deliver.”

Asked if that would involve a royal commission, Mr Streeting said: “I would definitely like to take other parties up on their offer of constructive engagement. We are thinking of the best mechanism to do that.”

Mr Streeting, who said the NHS must “reform or die”, laid bare the scale of the challenge and said public health reform was a necessary part of the answer because it would reduce demand on GPs and hospitals, even if that meant being criticised for “nanny state” initiatives.

“The existential threat from the NHS is that this combination of rising chronic disease, growing ageing society and rising cost pressures do combine to basically make the NHS unaffordable in the longer term, as the system we know today, as a public service, publicly funded, free at the point of use.

“And I’m not prepared to surrender on those principles. I think those are the fair, equitable principles that underpin a civilised society.

“If we could afford it in 1948 we can afford it in 2048 and beyond.”