The NHS faces “intense” pressure as it enters its 75th year amid a record rise in demand for care and “the biggest financial squeeze in its history”, health service leaders have said.

And the waiting list – currently a record 7.4 million people in England – is set to grow further still, a health minister has said.

The threat of strikes, a lack of reform in social care and a rise in demand for emergency care are heaping pressure on the system, NHS Providers said.

But its chief executive, Sir Julian Hartley, said that the pressures cannot be solely blamed on the coronavirus pandemic.

It comes as the leading health think tanks said that public support for the NHS as it reaches its 75th anniversary is “rock solid”, but the service will not be around to celebrate its 100th anniversary without more investment.

The King’s Fund, the Health Foundation and the Nuffield Trust said the NHS has “endured a decade of underinvestment”.

On the pressure facing the NHS, Amanda Pritchard, chief executive of the NHS in England, said: “We have some huge challenges, no one is going to pull their punches on that.”

Referring to waiting lists, she told BBC Radio 4’s Today programme: “That’s why we’re doing so much now to try and make sure that we are tackling recovery, inevitably, that’s not an overnight thing, that’s going to take many years.

“We’ve said right from the beginning, that the pandemic was going to be, you know, at least a five-year challenge.

“So we’re on to that but we’re not stopping there – we’ve got to look to the long-term future; the work on prevention; on new technology or new treatments is just as important.”

Sir Julian told Sky News: “The NHS is under intense pressure, that’s absolutely clear.

“I’ve worked in the NHS 30 years and I think this is perhaps the most pressurised I’ve seen it in terms of all of the challenges, in terms of recovering from Covid… urgent and emergency care demand is hugely significant, and then, of course, all the background issues around an ageing population and so on.

“But it is important to remember that it wasn’t just the pandemic – from 2010 to 2019 the NHS spent 18% less than 14 other European countries, so in terms of investment in the NHS, and indeed social care. Those are critical issues to resolve.

“The overall size of the waiting list is still a major issue.”

He continued: “I would say the pressures are enormous. There are things that the NHS is doing… but all of that is against the backdrop of enormous pressures of industrial action, of the biggest financial squeeze the NHS has seen for some time.”

Challenged on the 7.4 million figure, health minister Maria Caulfield told Sky News: “That probably will go up higher because we are offering more procedures.”

But “the length of time people are waiting for their procedures is actually going down and that’s what matters to patients”, she added.

She said that the NHS will be “thriving” in 25 years’ time, despite the warning from the think tanks.

It comes as the Tony Blair Institute published a report which said the service “needs to transform if it is to survive”.

In his foreword to the report, Mr Blair mentions the private sector a number of times, urging the NHS to capitalise on the services available.

Ms Pritchard told BBC Radio 4’s Today programme: “There’s a consensus I think that there is going to need to be continuous investment in the NHS, but there’s also consensus that we’re going to need to keep reforming, keep changing, and that’s what the NHS has been doing for 75 years – we’re no longer the NHS of TB, the iron lung, the cottage hospital, now we’re genomic medicine, with virtual wards with blood tests for cancer.”

On the funding model for the service, she said: “I do think public opinion on this is actually really clear – whatever the frustration with current challenges, people are overwhelmingly supportive of the founding principles of the NHS, so care free when you need it and funded through taxation.”

She said, when looking to international comparisons, that “all health systems are under pressure… not just because we’ve had a global pandemic, but also because we’ve got a growing and an ageing population”.

Shadow health secretary Wes Streeting warned that the NHS will die without “the necessary investment and reform” to change and modernise.

“At the moment the NHS is in jeopardy. I’m anxious about the future of the NHS, as I think the rest of the country is,” he told Sky News.

Meanwhile, Ms Pritchard said the NHS is to launch a database which will identify which patients could become part of exciting tests for potential cancer vaccines.

“Shortly we’ll also have a database that’s going to allow us to bring blood samples, tissue samples, of patients together, so that we can identify people who would be most likely to benefit from being part of clinical trials for cancer vaccines,” she told BBC Radio 4’s Today Programme.

Celebrations to mark the anniversary are taking place across the health sector, with famous faces also paying tribute to the service.

Tennis player Sir Andy Murray shared his thanks for the “indispensable” NHS and spoke about how it has supported his family.

Hollywood actor Tom Hardy will be reading Zog And The Flying Doctors on CBeebies Bedtime Stories on Wednesday evening while artist Charlie Mackesy has created a special NHS75 illustration.

The Prince and Princess of Wales surprised NHS staff by dropping in for a tea party at a London hospital while the Duke and Duchess of Edinburgh will be joined by 1,500 health service staff, politicians and other supporters of the NHS at a special service at Westminster Abbey on Wednesday.

The first baby born in the health service, Nye Thomas, will also attend.

Speaking before the ceremony, she told the PA news agency the service is a “national treasure” and she feels it is her duty to inform others about its work.