Plans to mass test the whole population for Covid-19 could “fail miserably”, an expert on screening has warned.

Government proposals to push forward with Operation Moonshot could cost a reported £100 billion.

But academics have raised serious concerns about the project, including the efficacy of the tests.

They also warned that students who are tested for Covid before being allowed to return home for Christmas must have clear information that a negative test result “reduces the risk” they are taking Covid-19 back home to their families, but it will not rule it out.

And mass testing of the whole population before Christmas could see 400,000 unnecessarily self-isolating during the holiday period, they added.

Academics urged the Prime Minister to use the so-called Downing Street reset to review the programme in a “sensible and rational way”.

It is understood that Dominic Cummings will continue to work on Operation Moonshot while working from home until his permanent departure from Downing Street.

It worries me that ministers or whoever can wake up one morning saying 'let's spend £100 billion on this' and not have it scrutinised. It would be like building a Channel Tunnel without asking civil engineers to look at the plans.

They said the proposals have been developed without the UK National Screening Committee, the body responsible for advising Government on screening strategy.

And tests for Covid-19 are not perfect and could produce false positives and miss detecting some new cases.

Dr Angela Raffle, consultant in public health and honorary senior lecturer at the University of Bristol, said: “When I learned of the Moonshot proposals this seemed to me to be the most unethical proposal for use of public funds or for screening that I’d ever seen.”

She highlighted several problems, including the short period of time in which people need to be tested, that the planning and infrastructure is not in place, the cost and that the proposals have not been scrutinised by screening experts.

“It worries me that ministers or whoever can wake up one morning saying, ‘let’s spend £100 billion on this’ and not have it scrutinised,” she said.

“It would be like building a Channel Tunnel without asking civil engineers to look at the plans.

“Even if it could work the way we’re going about it is destined to make sure it will fail miserably.”

She added the proposals could also lead to a “chaotic scramble to have tests, which we don’t know will bring any benefit”.

Allyson Pollock, clinical professor of public health at the University of Newcastle, called for the Moonshot programme to be paused while the cost effectiveness is established.

She added: “It’s really important to understand that none of these tests are tests of infectiousness.

“And that is one of the myths that’s being propagated, and was being propagated in Liverpool – that you could have your test in the morning and if you were negative you could go about your business or go to funerals or go to the nursing homes, and you’ll be fine.”

She added: “There has been far too little scrutiny and oversight of these contracts, and they’ve been bypassing the procurement process.

“And there’s been little evidence to show that they are value for money.”

Prof Pollock continued: “We have to think very carefully before we spend a hundred billion pounds on programmes that we do not know and have no evidence that they will work.

“The evidence for screening is not there. The evidence around the tests is poor and weak at the moment, and needs to be improved. And we’re arguing the Moonshot programme, really should be paused, until the cost effectiveness and the value for money, of any of these programmes is well established.”

When asked about whether people would safely be able to see their families at Christmas if they had a test, Jon Deeks, professor of biostatistics at the University of Birmingham said: “We would end up with 400,000 people in the country getting false positive results.

“So their Christmas would then be in lockdown wrongly.

“And as we saw the test will only pick up people when they’re in their most viral point and probably the test results or are applicable for one day.

“It certainly isn’t a suitable way to make sure we have a safe Christmas.”

He said the concept of “test and release” – whereby someone could behave in a normal way after a negative result – was “dangerous”.

Prof Pollock added that the so-called reset in Downing Street would be a good opportunity to “review some of these big strategic programmes”.

“It’s a really good chance to start anew and to revisit all this in a very sensible and rational way,” she added.

“And to take advice from the experts, which is something that the Government has failed to do over Operation Moonshot.”

On the tests for students before they return home for Christmas, Prof Deeks added that students should see a negative test result as a “risk reduction”.

“You still have to think you’ve potentially got it,” he said.

“So it’s not going to rule out the fact that they’re taking Covid back home – it will reduce it, but it doesn’t stop it.”

The experts suggested that relying on rapid tests that give a result in minutes could mean that a high proportion of cases are missed with false negative results.

Prof Deeks said the Innova lateral flow tests – the test being used in the Liverpool mass screening pilot – said that the test detects 73% of cases when patients are tested on a site with experienced research nurses.

But this falls to 57% among self-trained staff members at a testing centre.

An evaluation by Oxford University and Public Health England workers at Porton Down concluded that the test has an overall sensitivity of 76.8% – but it detects almost all cases among patients with a high viral load.