Boris Johnson has promised all coronavirus test results will come back within 24 hours but the small print of his pledge excludes up to a third of them.
The prime minister said that by the end of the month all tests in hospitals, drive-through centres and mobile units would be processed within a day. At present less than half of all tests are back within 24 hours but 90 per cent are done within 48 hours.
The new commitment will not cover postal tests and might not cover those sent to care homes, Downing Street admitted later.
Thousands of people had self-isolated on the advice of a national contact-tracing system after coming close to coronavirus patients, Mr Johnson said. However, the government is yet to
