Coronavirus testing will be rolled out to people working in public services such as police, fire and prison staff, Health Secretary Matt Hancock has said.
Capacity was rising “sharply” but not as many NHS staff had come forward for tests as had been expected, he said.
No 10 said 18,665 tests were carried out in the 24 hours to 09:00 BST on Thursday but there had been capacity for at least 38,000.
Meanwhile, a health expert said the crisis could lead to 40,000 UK deaths.
Prof Anthony Costello, the director of University College London’s Institute for Global Health, told an online meeting of the health select committee that the UK was “too slow” to react on a number of fronts to the crisis which may have led to it