“Ballooning” NHS waiting times and delays getting vital treatment in A&E and cancer care is harming health and costing lives, according to a critical government-commissioned report.

People have “every right to be angry,” Sir Keir Starmer will warn on Thursday, adding the health service must “reform or die”.

Health Secretary Wes Streeting vowed to “turn the NHS around” after the review found it is still struggling from the effects of the pandemic, weakened by under-investment and missing key targets for treatment.

But the Conservatives said the government needed to turn “rhetoric to action” after scrapping its plans to reform social care and build new hospitals.

The report was the result of a nine-week review of the health service in England by the independent peer and NHS surgeon Lord Darzi.

He was asked by Labour, shortly after the election, to identify the failings in the health service, but his remit did not stretch to coming up with solutions.

His findings present a stark picture of a health service which he says is in a “critical condition”.

In a speech, the prime minister will respond to the report by promising “the biggest reimagining of the NHS” since it was formed, with a new 10-year plan for the health service to be published in the coming months.

He will propose three key areas of reform: the transition to a digital NHS, moving more care from hospitals to communities, and focusing efforts on prevention over sickness.

The report from the peer, who served as a health minister in the last Labour government, said the NHS was still struggling with the aftershocks of the pandemic and falling well short of its key targets for cancer, A&E and hospital treatment.

It said this was contributing to poor survival rates in cancer and heart disease, and falling rates of satisfaction.

The report said the NHS had been left chronically weakened by the policy of austerity of the 2010s and in particular a lack of investment in buildings and technology. This has left it with crumbling hospitals, fewer scanners than many other developed nations and years behind the private sector in terms of digital innovation.

This has contributed to falling levels of productivity in hospitals, with rises in staff not matched by increases in the numbers of patients being seen.

It has meant hospitals have been sucking up an ever-increasing amount of the budget, when more care should be shifted into the community.

Lord Darzi was also critical of the “disastrous” 2012 reforms introduced by the coalition government, which led to a shake-up of management structure in the NHS and acted as a distraction for the rest of the decade.

It said all this contributed to the NHS entering the pandemic in a depleted state, leading to the cancellation of more hospital treatments than any comparable country and the “ballooning” waiting list, which currently stands at 7.6 million.

Meanwhile, a surge in patients suffering several long-term illnesses, such as diabetes, high blood pressure and respiratory illness, is threatening to overwhelm the NHS alongside soaring levels of mental health problems among young people.

The report also warns rising levels of illness are risking economic prosperity, with 2.8 million people unable to work because of poor health.

Lord Darzi said: “Although I have worked in the NHS for more than 30 years, I have been shocked by what I have found during this investigation – not just in the health service, but in the state of the nation’s health.”

Although the report focused on the NHS, Lord Darzi also warned of the “dire” state of social care, which he said was not “valued or resourced sufficiently”.

The growing gap between people’s needs and availability of publicly-funded social care in England was placing “an increasingly large burden on families and on the NHS”, he said.

In his speech, Sir Keir will say the 2010s were the “lost decade” for the NHS and add: “People have every right to be angry. It left the NHS unable to be there for patients today, and totally unprepared for the challenges and opportunities of tomorrow.

“The NHS is at a fork in the road and we have a choice about how it should meet these rising demands.

“Raise taxes on working people or reform to secure its future. We know working people can’t afford to pay more, so it is reform or die.”

He will also say waiting times in A&E are leading to avoidable deaths, adding: “People’s loved ones who could have been saved. Doctors and nurses whose whole vocation is to save them – hampered from doing so. It’s devastating.”

Shadow health secretary Victoria Atkins said the government had still yet to come up with meaningful plans for reform.

“The Labour government will be judged on its actions. It has stopped new hospitals from being built, scrapped our social care reforms and taken money from pensioners to fund unsustainable pay rises with no gains in productivity.

“They need to move from rhetoric to action.”

She also defended the Conservative government’s record, pointing out the NHS budget had been increased during the last Parliament.

Thea Stein, chief executive of the Nuffield Trust think tank, said while Lord Darzi’s report was “not surprising” it was still “deeply troubling”.

“The big question now is what happens next.”

William Pett, of the patient watchdog Healthwatch England, said the problems needed to be addressed, describing services as in disarray and waiting times as excessive.

And he added: “These challenges are not experienced equally, with poorer communities hit hardest.”