Hundreds of scientists have warned the British government that their response to the coronavirus epidemic is “risking many more lives than necessary”.

In an open letter published on Saturday night, more than 295 academics living and working in the UK backed calls for immediate measures to restrict the spread of Covid-19.

They criticised the UK’s strategy of delaying restrictions in a bid to achieve ”herd immunity”, arguing that it would put the NHS under even more stress.

“By putting in place social distancing measures now, the growth can be slowed down dramatically, and thousands of lives can be spared,” the letter adds.

“We consider the social distancing measures taken as of today as insufficient, and we believe that additional and more restrictive measures should be taken immediately, as it is already happening in other countries across the world.”

The letter adds to the pressure on Boris Johnson to act quickly following confirmation that 10 more coronavirus patients have died, nearly doubling the total in one day to 21. The number of confirmed cases increased to 1,140.

France and Spain have both imposed partial lockdowns, including closures of most shops, cafes and restaurants. Italy, which has the highest number of cases outside China with more than 21,000, is already under total lockdown.

The government responded to the letter by saying that “we will be instituting our next planned interventions soon.”

“We will publish the modelling and data considered by Sage [the government’s Scientific Advisory Group for Emergencies],” a spokesman added. ”We continue to be guided by the advice of the chief medical officer and the chief scientific adviser.”

Meanwhile the Department of Health and Social Care rejected the criticisms stated in the letter.

“Herd immunity is not part of our action plan, but is a natural by-product of an epidemic,” a spokesman said. “Our aims are to save lives, protect the most vulnerable, and relieve pressure on our NHS.”

The letter has been signed by a wide range of scientists at UK universities, including professors, lecturers and PhD students in mathematics, biology, medicine and computer science.

Additional reporting by Press Association