Britain on Thursday said it was in discussions with Swiss pharma giant Roche to mass purchase its coronavirus antibody test after scientists claimed it was "100 percent" accurate.

"This test developed by Roche appears to be extremely reliable, it's got the green light from testers," health minister Edward Argar told the BBC on Thursday.

"We are currently in discussions with Roche about that. We are very keen to get that test on stream as swiftly as we can," he added, calling it a potential "game-changer".

The antibody tests, which Roche said had been given approval by the US Food and Drug Administration and the European Union, detect whether someone has had coronavirus at any point in the past.

Britain has had more than 36,000 deaths in the outbreak -- the second-worst in the world -- but has partially lifted lockdown measures in England this week.

The government has been accused of putting workers' lives at risk by easing restrictions while the daily death toll is still hovering around 500.

But ministers and scientists are banking on a reliable antibody test to give people the confidence to go back to work, even if it is not yet clear just how much immunity people have against developing COVID-19 again.

The Office for National Statistics (ONS) meanwhile published figures estimating that 148,000 people in England were infected with the virus over the past two weeks.

That is the equivalent of approximately 10,000 new infections per day between April 27 and May 10.

The ONS tested 10,705 people in 5,276 households and estimated that 0.27 percent of the English population are currently COVID-19 positive.

Of those working with patients in healthcare roles, including doctors, nurses and those in care homes, the estimates were higher, at 1.33 percent.

The survey is designed to help track the current extent of infection and transmission in the community, and will help guide the government's response to the outbreak.

'Positive development 

Roche's SARS-CoV-2 serology assay has been tested by scientists at Public Health England's research laboratory at Porton Down, in southern England.

The national coordinator of the UK Coronavirus Testing Programme, Professor John Newton, said they concluded it is a highly specific assay with a specificity of 100 percent".

"This is a very positive development, because such a highly specific antibody test is a very reliable marker of past infection," Newton said. 

"This in turn may indicate some immunity to future infection, although the extent to which the presence of antibodies indicates immunity remains unclear."

Prime Minister Boris Johnson's official spokesman said evaluation regarding immunity could "inform future decisions on rolling out antibody testing to the general public".

That could lead to consideration of an "immunity certificate", he told reporters.

Ravi Gupta, a professor of microbiology at the University of Cambridge, called the antibody test results "welcome".

"The Roche test is unlikely to give false results based on the information available," he said.

"But it needs to be done in a dedicated hospital or central laboratory on specialised machines and therefore turnaround time for results is likely to be at least a day or more."

Separately, NHS England for the first time published details of the pre-existing conditions the 22,332 people who had died in the coronavirus outbreak since March 31.

Some 5,873 had diabetes, 4,048 had dementia, 3,254 had chronic pulmonary disease, and 1,549 patients had asthma.