In Germany, researchers are planning to send out hundreds of thousands of tests to establish how many people have built up immunity

Every NHS worker forced to self-isolate has been promised a coronavirus test by the end of the month as the health secretary set a new target of 100,000 tests a day.

Matt Hancock has responded to public anger over the lack of testing with a five-point plan in what aides acknowledge is a significant gamble.

The plan includes the use of commercial labs and confirmed that an immunity test was being used to carry out a “poll” of how many people had been infected.

Matt Hancock said that he had come out of self-isolation determined to beat the coronavirus GETTY IMAGES

Companies have responded with scepticism after Mr Hancock promised, in effect, to create a British diagnostics industry from scratch in the coming weeks. An industry source said that at a meeting with Mr Hancock “no specific dates or numbers were sought