Britain was hit far harder by the Covid-19 pandemic than other developed countries because the NHS had been “seriously weakened” by disastrous government policies over the preceding decade, a wide-ranging report will conclude this week.

An assessment of the NHS by the world-renowned surgeon Prof Ara Darzi, commissioned in July by the health secretary, Wes Streeting, will find that the health service reduced its “routine healthcare activity by a far greater percentage than other health systems” in many key areas during the Covid crisis.

Hip and knee replacements, for instance, fell by 46% and 68% respectively. Hospital discharges as a whole dropped by 18% between 2019 and 2020 in the UK compared with the Organisation for Economic Co-operation and Development average of 10%, Lord Darzi will say.

In a key section of his report, the crossbench peer will also conclude that the NHS is still suffering the aftereffects of its inability to respond adequately to the Covid shock at the time.

“The state of the NHS today cannot be understood without recognising quite how much care was cancelled, discontinued, or postponed during the pandemic … The pandemic’s impact was magnified because the NHS had been seriously weakened in the decade preceding its onset.”

Darzi will be particularly critical of former Tory health secretary Andrew Lansley’s top-down reorganisation of the NHS under David Cameron’s prime ministership, which he will say “scorched the earth for health reform”.

“The Health and Social Care Act of 2012 was a calamity without international precedent – it proved disastrous,” Darzi will say, adding: “The result of the disruption was a permanent loss of capability from the NHS … This is an important part of the explanation for the deterioration in performance of the NHS as a whole.

“Rather than liberating the NHS, as it had promised, the Health and Social Care Act 2012 imprisoned more than a million NHS staff in a broken system for the best part of a decade.”

Lord Lansley defended his reforms, saying Darzi should be focusing on the “here and now” rather than reaching back over a decade for a “blame the Tories” narrative.

“The 2012 act created NHS England. It empowered the NHS. It reduced administration costs by £1.5bn. Waiting times fell to their lowest level. The longest waits were virtually eliminated,” said Lansley. He added that if his plans had been fully implemented, they would have made the NHS more internationally competitive.

The Tories are preparing to criticise the Darzi report as politically driven because its author was a minister under the previous Labour government and was a member of the Labour party until he resigned in 2019.

Labour will, however, point to his impressive CV and the fact that he held prominent positions while the Tories were in power, including sitting as the UK global ambassador for health and life sciences from 2009 until March 2013. Also, in 2015, Darzi was appointed as nonexecutive director of the NHS regulatory body Monitor, which oversaw the quality and performance management of healthcare in England.

The Darzi report – which will also find that more than 100,000 infants (0 to two-year-olds) were left waiting for more than six hours in A&E departments in England last year – is being seen as a watershed moment by senior NHS figures.

Streeting is expected to use the report as the foundation for his own blue-sky thinking on reform. The current NHS England long-term plan introduced in 2019 was drawn up before the pandemic, which has caused waiting lists to lengthen to a point where 6.39 million people are waiting for 7.62m treatments.

Streeting said last year that he believed the NHS required three big shifts, from sickness to prevention, from hospitals to GPs and community services, and from an “analogue service to one that embraces the technological revolution”.

Two other key reports to be published this week also paint a bleak picture of the health service’s prospects under current spending constraints.

A survey of trust chief executives and finance directors by NHS Providers, the membership organisation for hospital, mental health, community and ambulance service users, has found more than half (51%) to be “extremely concerned” about their ability to deliver on their priorities within the tight financial limits for 2024-5.

Nine out of 10 thought the financial situation more challenging than last year. Among the measures they were having to consider were “extending vacancy freezes”, “reducing substantive staffing numbers” and “scaling back services”.

Sir Julian Hartley, chief executive of NHS Providers, said that with funding so tight the message was that ways had to be found to secure multi-year investment in reforms that would increase productivity “instead of this stop-start approach to NHS funding which leaves them constantly worrying about budget cuts followed by quick fix, short- term funding announcements”.

In addition, a report from the NHS Confederation and healthcare consultancy CF (Carnall Farrar) has found that Labour’s pledge to create an extra 40,000 appointments a week in England would not stop waiting lists from rising.

It would only deliver 15% of what was needed to ensure 92% of patients start routine hospital treatment within 18 weeks – a key target that has not been hit for nearly a decade.

Matthew Taylor, chief executive of the NHS Confederation, said it was unlikely that there would be any significant reduction in waiting lists until spring or summer next year.

He added: “We need to be realistic about the fact that unless we do some pretty transformative stuff, demand is going to grow substantially. Almost everyone agrees we need to transform the NHS by investing in prevention. To do that, you have to double run [opening new services before old ones close].

“None of those things can be achieved for free. What we need from Rachel Reeves is a recognition that the long-term sustainability of the health service, the public sector and the economy as a whole, rests on shifting the health demand curve.”

Speaking to the BBC’s Laura Kuenssberg on Sunday morning, the prime minister, Keir Starmer, will echo Darzi’s assessment, saying the Tories “broke” the NHS in ways that were “unforgivable”.

He will add: “Our job now, through Lord Darzi, is properly to understand how that came about and bring about the reforms, starting with the first steps, the 40,000 extra appointments.”

A Conservative Party spokesman said:

“The NHS has more doctors, more nurses, more funding in real terms and is looking after more people than ever before.

“During this once in a lifetime international emergency, the NHS looked after millions of people well. The UK Government rolled out a safe and effective vaccine faster than anyone else in the world whilst saving whole sectors, millions of jobs and thousands of businesses.

“And we wanted to learn lessons which is why we set up the Public Inquiry. It is odd that this former Labour Minister and peer feels he is in a better position to opine on Covid than the Public Inquiry.”