The test and trace system launching in England on Thursday is the key that will "unlock the prison" of lockdown, the prime minister has said.
Boris Johnson said the tool "will allow us, gradually, to release 66 million people from the current situation", with Scotland, Wales and Northern Ireland running their own versions.
So, how will the NHS England test, track and trace programme work?
If you suspect you have coronavirus, you can order a test by dialling 119 or visiting NHS.uk/coronavirus.
If your test comes back positive, you will be asked to give details of people you have been in "close contact" with. That is defined as people you have been within two metres of for more than 15 minutes without protective equipment.
Those people who have been in close contact with you will be contacted by NHS Test and Trace and told to isolate for 14 days, even if they are asymptomatic.
This scheme differs from the contact tracing app currently being tested on the Isle of Wight, which also identifies people unknown to someone who tests positive.
More from Covid-19
While asymptomatic people will be told to isolate, existing rules will still apply, meaning anyone who develops symptoms should isolate for seven days and the remaining members of their household for 14 days.
How many people are involved in running the system?
About 50,000 – a mix of testing staff and contact tracers including roughly 7,000 clinicians. They will get to start contacting people from 9am on Thursday, starting with people who received a positive test the day before.
How long will people need to wait for the results of a test?
The government has not given detail on this, but it does not expect all results will be confirmed within 24 hours.
Experts have raised concerns about this, saying people who unknowingly have coronavirus could go on to infect others before receiving their results.
Officials say they're instead focused on the process from start to finish – from the test being ordered to contacts being traced.
If I'm contacted by the NHS, will my whole household need to isolate?
No. Health Secretary Matt Hancock told Wednesday's coronavirus briefing that "if you have been contacted by NHS and you are instructed to isolate, your household members do not need to isolate – they can carry on going on with their normal lives".
This differs from the government guidelines which state that if you are living with someone who displays coronavirus symptoms, you and everyone else in the house need to isolate for 14 days.
How will the system be enforced?
Initially the system will rely on people choosing to follow the guidance if Read More – Source