UK regulators will this week announce approval criteria for firms offering new coronavirus antibody tests.

The antibody tests show whether people have been infected with COVID-19 and developed immunity, potentially allowing them to return to their places of work.

The UK government as provisionally orders 17.5 million of them, but health minister Matt Hancock said some of those already being trialed work poorly, and that one test even missed three out of four cases.

"How they fail tests when there is no specification, I literally have no idea. We have been begging to be told what to do. We have a test ready to submit," said Brigette Bard, chief executive of the diagnostics firm BioSure.

Bard met Prime Minister Boris Johnson in March to discuss her COVID-19 test.

BioSure has been producing an at-home HIV test since 2015.

Bard said laboratory trials were producing good data, but that the firm needed to know what size and scope of trial and what accuracy level would be accepted by regulators.