A first coronavirus antibody test could be approved by Public Health England (PHE) this week, with hundreds of thousands available each week if officials give the green light.
Government scientists are currently evaluating the accuracy of a test made by Roche, which was cleared for use by the US Food and Drug Administration on Saturday.
They are expected to report their findings by the end of the week, the Swiss manufacturer said last night.
Designed to detect whether a person has previously contracted Covid-19, and therefore whether they are likely to be immune from further infection, the technology is considered vital to lifting the lockdown safely.
It could enable family members with a positive result to interact with vulnerable older relatives confident that they are not placing them at risk.
Some experts have also suggested it could be allied to an immunity passporting system, whereby people able to prove they have previously fought off the virus would be granted greater freedoms under a partial lifting of restrictions.
The new Roche test is one of a handful from reputable producers that have secured a European Union CE marking – denoting conformity with health and safety standards – in recent days.
These include Abbott Laboratories, an American producer which has also secured emergency FDA approval, and Quotient, a UK firm, which says it could process 36,000 tests a day.
Together, they raise the prospect of widespread access to antibody testing this month, an ambition endorsed on Sunday by Professor John Newton, the national testing coordinator.
“There has been a lot of work in antibody testing. We are optimistic that we will have a good antibody test when we need it,” he told the BBC.