A test to find out whether people have ever been infected with coronavirus has been approved by health officials in England.

Public Health England said an antibody test developed by Swiss pharmaceutical company Roche is a “very positive development”.

The blood test looks for antibodies to see if a person has already had the virus, and may now have some immunity.

Until now, officials had said these tests were not sufficiently reliable.

But sources say this is the first one to offer serious potential.

Experts at the government’s Porton Down facility evaluated the test last week, Public Health England said, and found it to be “highly specific”.

Prof John Newton, national coordinator of the UK coronavirus testing programme, said: “This is a very positive development because such a highly specific antibody test is a very reliable marker of past infection.

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

Roche is understood to be in talks with the Department of Health and Social Care about possible use by the NHS in England, though other testing products are also being assessed.

Health officials in Scotland, Wales and Northern Ireland make their own decisions, but are likely to follow suit if England does adopt it.

The device already has approval from medical regulators in the EU and the United States.

But it is not yet clear what amount of immunity from coronavirus a patient might gain from having previously been infected.