A quarter of a million people are being recruited for an NHS volunteer army as retired doctors and medical students are called up to help to run a 4,000-bed hospital in a London conference centre.

Chris Smyth, Whitehall Editor | Rhys Blakely, Science Correspondent www.thetimes.co.uk

Matt Hancock, the health secretary, has issued a “your NHS needs you” appeal to those willing to look after 1.5 million vulnerable people being “shielded” from coronavirus.

He is under pressure, however, to spell out when tests for the virus will be available for NHS staff, despite promising to “ramp up” existing labs and order 3.5 million commercial kits.

Oxford University researchers said yesterday that half of Britain might have already contracted coronavirus since January and that testing was urgently needed to discover how many people had acquired immunity to it.

Professor Sunetra Gupta, whose conclusions have not yet been peer- reviewed, said: “It is possible that this ends with a whimper not a bang — we need to know.”