The Government is mulling shelling out up to £100 billion for a mass at-home coronavirus testing programme, but experts are cautious about its ability to deliver.

Known as “Operation Moonshot”, it could see up to 10 million tests carried out every day from the comfort of people’s own homes.

Here’s what we know so far.

– How will Operation Moonshot work?

Ministers and health officials are banking on a test that does not need to be processed in a lab to be developed, so that users get their results in a matter of minutes rather than days.

Similar to a pregnancy test, the saliva test would eliminate the need for people to travel – sometimes long distances – to testing centres before returning home to wait for the result.

-Does such a test exist?

Scientists have warned that, as yet, a reliable at-home test has yet to be developed – meaning that it will be some time before we can rely on it to help us return to normal.

Chief scientific adviser Sir Patrick Vallance said on Thursday: “There are prototypes which look as though they have some effect, but they’ve got to be tested properly.

“We would be completely wrong to assume this is a slam dunk that can definitely happen.”

– How much will it cost?

Operation Moonshot will have a price tag of almost as much as NHS England’s £114 billion budget in 2018/19, as set out in documents seen by the British Medical Journal.

Last week the Government pledged £500 million for a new community-wide repeat testing trial in Salford, Greater Manchester, as part of pilot scheme for a no-swab saliva test.

A number of residents will be invited for a weekly test, with up to 250 carried out each day, while existing trials of tests in Southampton and other parts of Hampshire will also be expanded.

– What is the Government hoping for?

The aim of the tests is to start fully reopening society and getting the economy up and running even before a vaccine has been developed.

After imposing stricter social distancing measures limiting groups meeting indoors or outdoors to just six people, with the threat of a fine for non-compliance, the Government is in dire need of some good news.

Previewing the plans, Prime Minister Boris Johnson said the programme would allow Covid-negative people to “behave in a more normal way in the knowledge they can’t infect anyone else with the virus”.

– What do the experts say?

If all goes to plan, it could open up the economy, potentially spelling the end to everything from quarantine for holidaymakers to spectator bans at sports events.

But leading statistician Professor Sir David Spiegelhalter said the “huge danger” was that there could be a “very large number of false positives”.

That would result in large numbers of people self-isolating unnecessarily, which could actually end up damaging the economy.

– What are the problems with the current testing programme?

There have been numerous reports of people being asked to travel long distances to their nearest testing centre, only to discover that they do not have an appointment.

One man, from Maidstone, Kent, who asked not to be named, revealed to the PA news agency that he was asked to make a 400-mile round trip for a test, only for his results to then be lost.

On Wednesday, Health Secretary Matt Hancock also blamed the shortage of testing slots on symptom-free people attending for a test, despite the fact people can be symptom-free and still spread the virus.

– When will this new ‘Moonshot’ testing be available?

Transport Secretary Grant Shapps was sent out to defend the plans on Thursday morning, but he declined to give a timeframe.

He was realistic about the fact that it could be a long time before a reliable test is ready, saying: “This is technology that, to be perfectly blunt, requires further development – there isn’t a certified test in the world that does this but there are people that are working on prototypes.”