Future medical advances are at risk because NHS pressures are hampering the ability of staff to take part in vital research, leading academics say.
The Academy of Medical Sciences said the number of doctors involved in research had fallen, while budgets had been frozen.
It said despite shortages of staff on the front line, more priority still needed to be given to research.
The government said it was looking to invest more in research generally.
During the election, the Tories said they wanted to see funding double over the next five years to £18bn a year.
That is for the whole research sector – although the NHS is expected to be a major beneficiary of this.
The Academy of Medical Sciences said this would help, but NHS staff would need protected time to ensure they could take part in research.
It wants to see a pilot scheme launched involving 10 UK hospitals which would allow one in five consultants to have one day a week to carry out research.
Academy of Medical Sciences president Prof Sir Robert Lechler said investing in research was “critical” and needed to be prioritised even at a time when the NHS was struggling with a shortage of doctors and nurses.
“We are enjoying an exciting era of unprecedented medical discovery.
“Patients need us to convert this progress into new cures and better care.”
NHS ‘vital for research’
The report by the Academy of Medical Sciences said the NHS had played a vital role in a number of important discoveries, including the link between smoking and lung cancer, and medical advances which led to progress on organ transplantation, stem cell research and the invention of MRI scanning.
Every year, more than one million people take part in research programmes involving the NHS.
All NHS trusts are involved in one way or another, whether that involves participating in trials or data analysis.
Much of the work relies on senior doctors taking on academic roles in partnership with universities to lead programmes.
But the proportion of consultants in England involved in such arrangements has fallen from 7.5% in 2004 to 4.2% in 2017, the report said.
This has happened as the budget for the National Institute for Health Research, the main funding body for the sector, has seen its budget frozen in recent years, the report added.
Spending by pharmaceutical companies in the UK has also fallen.
A spokesman for NHS England said research programmes in the health service were still growing despite the pressures.
“As NHS staffing expands further over the next five years, the opportunities for more research will increase.”