Just 3% of medical research charities are eligible for Government funding and that is causing life-saving work to be cancelled, Labour has claimed.
The party said charity-funded research has been severely impacted by Covid-19, with charities projecting it will take more than four years for spend to recover to normal levels.
Charity funding for medical research has plunged by 41%, the party said, adding only five of 152 medical research charities (3%) are eligible for Government support.
Important medical studies said to be stalled or cancelled include those tackling dementia, coronary heart disease and cancer, which could have long-term consequences for hundreds of thousands of patients.
Labour is warning that with around half of all medical research spend coming from charities, the impact on scientific progress could be stark.
“The UK gets great returns on research funding, both in terms of our economy and in the positive impact for those that rely on breakthroughs in treatment.
“The Government needs to urgently listen to the sector and address their concerns. Cold-shouldering these charities now will have huge ramifications down the line.”
Aisling Burnand, chief executive of the Association of Medical Research Charities, said: “A statistic will never truly capture the devastating impact research cuts will have on all of us.
“Research is hope. Research is more time with your loved ones. Research is improved quality of life.
“Its value is immeasurable. By committing to a Life Sciences-Charity Partnership Fund, Government can help deliver a better future for countless people across the UK.”
Last month, Cancer Research UK said its planned research spend over the next four to five years needs to reduce by £150 million.
It also announced plans to cut almost a quarter of its jobs, with up to 345 redundancies over the next six months.
In June, British Heart Foundation chief executive Charmaine Griffiths said it is losing £10 million a month, even with support from the furlough scheme.
A spokesperson for the Department of Health and Social Care said: “The UK is home to many globally-recognised medical research charities, which are an integral part of our world-leading life sciences sector.
“The government is committed to supporting research. So far, 27 research projects have received a share of a £25 million investment and £750 million has been given in support to the charity sector.
“We are in continuous dialogue with these charities as we assess the impact of this unprecedented pandemic, to ensure patients continue benefiting from charity-funded research.”