A team of 25,000 contact tracers will make their first phone calls within hours – to track down people who will be told to self-isolate under the new test and trace scheme in England.
Tracers will text, email or call people who test positive with coronavirus and ask who they have had contact with.
Any of those contacts deemed at risk of infection will be told to isolate for 14 days, even if they are not sick.
The prime minister said the system will “change people’s lives”.
The aim of the NHS Test and Trace system is to lift national lockdown restrictions and move towards more localised, targeted measures.
The contacts of people who tested positive will be the first to be chased by the NHS Test and Trace team today, Health Secretary Matt Hancock said.
Northern Ireland has its own version of the programme up and running, while Scotland has announced its own system will start Today and Wales’ scheme is due to start in early June.
Plans for an app to automatically alert people they have been in contact with someone who has tested positive are still being trialled on the Isle of Wight and the government still hopes to have that system up-and-running by next month.
The government’s plans to ease lockdown measures – including to begin a phased reopening of schools from next week – will be confirmed in an official review later.