“About two weeks ago one of my colleagues spent two days trying to be a bit irritating and chasing PHE up to offer our help. There was a lot of general enthusiasm - they said, ‘Oh that’s great and we’re really happy that you want to help’. And then nothing really came of it. That’s been the same for many institutions across the country. I can’t really understand why.”

A source at Public Health England said Prof Freeman was referring to work led by the Department of Health to scale up mass testing at the planned “super lab” in Milton Keynes.

At the Francis Crick Institute, one of the world’s leading biomedical research centres based in London, insiders told a similar story.

The institute has supplied five PCR machines to PHE labs so far, but is understood to have dozens more inside its labs. A spokesman added that no firm word had yet been received from PHE as to whether any further machines or expertise would be required.

“We have hundreds of scientists with different areas of expertise ready and willing to step in to help support the national drive to tackle the outbreak,” the spokesman told The Telegraph.

"We were approached by Public Health England for support with their testing programme, and have already sent 5 PCR machines to support it. We are supportive their work at this really difficult time, are ready and enthusiastic to help with the testing programme, and recognise that setting it up and then scaling it can’t be done overnight."

Other institutions across the country are understood to have had similar offers of help rejected by Public Health England.

Ministers are acutely aware that Britain’s failure to carry out more tests has become the weak leak in the response to the pandemic, and are desperate to ramp up mass testing.