A COVID-19 test and trace service will start in England on Thursday to allow the loosening of lockdown measures for most of the population, Prime Minister Boris Johnson said.
"(From tomorrow) there is a new test and trace operation which will change people's lives and which will require a great deal of thought and compliance but which I think will be worth it for the whole nation," Johnson told lawmakers on Wednesday.
The service, which will have a task-force of 40,000 specialists to test those with symptoms and identify their contacts, will not initially include the app that is key to finding anonymous contacts.
Health Secretary Matt Hancock said the app, which is being trialled on the Isle of Wight, would be rolled out when the system was "bedded in".
Contacts will be instructed to isolate for 14 days, even if they have no symptoms, Johnson said, adding that it was a "huge imposition" but it would only apply to a "very, very small minority of the population".
"It's worth it because that is the tool that other countries have used to unlock the prison, to make sure that we can go forward," he said.
"That captivity for a tiny minority for a short time will allow us gradually to release 66 million people from the current situation."
He said the system would initially rely on the "public spiritedness" of Britons, but sanctions could be imposed if people did not comply.
Britain abandoned test and trace in March when the virus started spreading exponentially and there was insufficient capacity to test more than a fraction of those with symptoms.
Health Secretary Hancock said there was now enough capacity - some 161,000 tests a day - for all who needed one to be tested.
Dido Harding, who is heading the programme, said it would enable the national lockdown, which has been in place since March 23, to be replaced by individual isolation and local action where cases start to spike.
She said the average number of contacts for an individual would be around five, down from about 30 before the health crisis because of the impact of social distancing.
Scotland, Wales and Northern Ireland have similar programmes just about to launch or already running.
(Additional reporting by William James and William Schomberg, editing by Elizabeth Piper and Stephen Addison)
