The NHS will have to divert £45bn from essential services to pay for new medicines under the terms of the UK-US trade deal agreed last December, leading to more than 200,000 avoidable deaths of patients, analysis has found.

Ministers have defended the deal as a way of helping British drug exports to the US avoid tariffs, and giving patients in England access to potentially life-extending drugs that would otherwise be denied.

But they have been accused of caving in to US demands to spend billions of pounds a year extra on drugs supplied to the NHS after pressure from Donald Trump. The potentially devastating impact on NHS care has also caused growing alarm among health experts.

Now analysis, published in the British Medical Journal, lays bare the likely cost of the deal to the NHS – and the projected deadly impact of cuts to health services on the population in England – for the first time.

In total, £44.7bn in NHS cash will be diverted from health services by 2036 in order to pay more for new medicines under the trade deal, unless extra funding is made available to cover the additional costs, the analysis suggests.

Reduced NHS spending on services will have an adverse effect on the nation’s public health, the analysis found, causing 229,000 excess deaths by 2036. The estimated avoidable death toll is larger than the number that occurred during the Covid-19 pandemic, between March 2020 and June 2022 (137,000).

If the indirect effect on adult social care was also included, excess deaths would increase to 291,000, the report from the University of York, the University of Liverpool and Christchurch hospital in New Zealand found. Most of the preventable deaths would be among people with heart, respiratory and gastrointestinal disease or cancer.

When the agreement was reached last December, ministers hailed the deal as a “landmark” to “safeguard medicines access and drive vital investment for UK patients and businesses.”

The UK agreed to pay 25% more for new medicines over the next decade. The deal will also see the health service in England, which currently spends £14.4bn a year on innovative therapies, double the percentage of GDP it allocates to buying such products, from 0.3% to 0.6% over the next decade.

Ministers and drug industry bosses said the deal was good news because it would let British-made drugs sold to the US avoid tariffs of up to 100% that Trump threatened to impose on some medicines being imported into the US.

But MPs and campaign groups voiced scepticism. The deal will lead to the NHS axing services “to pacify Donald Trump and big pharma’s demand for higher medicines prices”, the UK-based campaign group Global Justice Now has previously warned.

MPs from Labour and several opposition parties have also urged the government to publish its own secret impact assessment of the trade deal it reached in December with the Trump administration.

The government says the deal will cost only an extra £1bn between 2025-26 and 2028-29. It has admitted costs will rise after 2028-29, but has not given any estimates of that.

In February, Patrick Vallance, the science minister, disclosed that the costs would be borne by the Department of Health and Social Care, which funds the NHS in England, and not the Treasury.

The BMJ analysis suggests the annual cost to the NHS will surge to £8.8bn by 2036, with the total bill hitting £44.7bn by the end of that year.

Sir Ciarán Devane, the chief executive of the NHS Alliance, which represents the healthcare system in England, Wales and Northern Ireland, said the analysis raised “serious questions” over whether the trade deal represented value for patients or for the NHS.

“If billions of pounds are diverted away from frontline care to meet higher medicines costs, the consequences for prevention, community services and the treatment of long-term conditions could be profound. The government must urgently publish the full impact assessment and ensure there is appropriate scrutiny of the deal if it could have such far-reaching implications for population health.”

Helen Morgan, the Liberal Democrat health spokesperson, said the analysis was “alarming” and called on the government to urgently publish its own impact review of the UK-US agreement.

Morgan said it was “crazy” that billions of pounds in NHS funding were being spent on placating Donald Trump. “It is a complete insult to patients who are suffering and dying on hospital trolleys and waiting months for treatment. We cannot afford to sit by while our NHS is picked apart by a foreign regime. We need to defend our NHS with everything we have and firmly stand up to the bully in the White House.”

Tim Bierley, a campaigner at Global Justice Now, said: “Billions that could be spent on recruiting more NHS staff, cutting GP waiting times, or improving our hospital care are set to be siphoned off by corporate giants in the pharma industry. As the research shows, if money is diverted from other critical parts of our NHS to pay for this deal, this would lead to hundreds of thousands of deaths.

“Scandalously, this backroom deal was not subject to any scrutiny in parliament before being rushed through – and the government refuses to say what impact it will have on the NHS. The next prime minister must change direction, stand up for our NHS, and unpick the mess left by their predecessors.”

Diarmaid McDonald, the executive director of the patient campaign group Just Treatment, said: “These numbers should shock people to their core. Tens of billions of pounds taken out of the NHS budget and put into the back pockets of the pharmaceutical industry, placing hundreds of thousands of lives at risk.

“Across the country, our parents, our grandparents, our loved ones, dying unnecessarily in order to inflate drug company profits and please Donald Trump. This is a national scandal.”

A Department of Health and Social Care spokesperson said: “Through our partnership with the US, we have reformed medicine pricing, allowing NHS patients to access life-changing new medicines they previously would have been denied. We are also making the UK one of the best places in the world to develop, launch and manufacture new medicines.

“The £45bn figure is not recognised by the department. The deal will be funded by allocations made at the spending review, where record funding for the NHS was secured. Future funding will be settled at the next spending review.”