Boris Johnson has said he has “great confidence” that by June 1 there will be a test, track and trace system in place to allow the UK to continue to reduce coronavirus cases.
Widespread contact tracing was abandoned in the middle of March as the number of cases soared in the UK, but it is now seen as a crucial part of efforts to safely ease the lockdown.
In a nutshell, test, track and trace – TTT – means testing people for coronavirus, tracking the spread of the virus, then tracing the people an infected person has come into contact with.
But what exactly does TTT involve and why is it so important?
The first part of this method is to test widely for those who have coronavirus symptoms, not those who think they have had the illness in the past.
The test is now available to anyone over the age of five who has symptoms, having previously been only for key workers.
The test involves taking a swab of the nose and the back of the throat and can be done by booking a slot at a drive-through test centre, or ordering one online.
If someone tests positive, they will then need to isolate for at least seven days.
Anyone living with a person who tests positive should self-isolate for 14 days.
Results should be available within two to three days.
The government wants to track Covid-19 in the population to try to understand the current rate of infection alongside how many people have developed antibodies to the virus.
As more and more people are tested, authorities will be able to identify those who have the virus, therefore keeping track of who they are and where they are.
This will give an idea of the spread of the virus and highlight areas of the country worse hit than others.
Once someone has tested positive, contact-tracing will be essential to slow the spread.
An NHS app for this is currently being trialled in the Isle of Wight.
It is hoped the app will identify people who have been in proximity to a smartphone user who subsequently develops coronavirus symptoms and tell them to self-isolate, without revealing the identity of the person infected.
For this app to be successful, it is believed at least 60% of the population must download the software onto their smartphones.
However, there is no set date for the app to be rolled out, with the government saying it hopes it will be available in the "coming weeks", having previously said it hoped the app would be in use by mid-May.
In addition, thousands are now being recruited to help with manual contact tracing.
They will help notify those who have come in contact with someone who has tested positive for coronavirus.
Boris Johnson said in May that 25,000 staff would be in place by the start of June and they would be capable of tracking the contacts of up to 10,000 new Covid-19 cases a day.
The more information the government gathers on the spread of the virus, the more likely those infected can be kept separate from the rest of the population by quarantining themselves at home.
If the UK can control the spread in this way, the lockdown could be eased sooner.
Why did we ever stop contact tracing?
Contract-tracing was stopped in mid-March as the number of coronavirus cases grew too rapidly for all contacts to be traced.
Deputy chief scientific adviser Professor Dame Angela McLean said focusing testing on hospital patients early on in the Covid-19 outbreak was the “right thing” to do.
At the Downing Street press conference on May 19, she was asked why community testing ended on March 12, when the World Health Organization had encouraged as much testing as possible.
“I think I would agree that at the time, with the testing we had, the right thing to do was to focus it on people who were really sick in hospital, so we knew who in hospital had Covid, so it was the right thing to do at the time,” she said.
She said the UK has looked closely at contract tracing systems in other countries and praised the work of South Korea, where “inspiring” contact tracing work has been done “to the extent that they are now down to handfuls of new cases every day”.
“I think that is an experience that we are aiming to emulate,” she said.
Why is South Korea a good example?
South Korea has been widely hailed as an example for all nations to follow.
One reason South Korea has managed to avoid lockdowns or business bans was because of its aggressive testing and contact-tracing program that draws from its experience of fighting a different coronavirus — MERS or Middle East Respiratory Syndrome — in 2015.
According to the Johns Hopkins University global tracker, there are little more than 11,000 confirmed cases in South Korea as of May 21 – with 264 deaths in total.
The population of South Korea is 51 million, while there are more than 66 million people in the United Kingdom.
The UK’s death toll is far greater and has surpassed 30,000.
Last week, South Korea reported 34 more cases as new infections linked to nightclub-goers threatened the country’s hard-won gains against the virus earlier in May.
But this was the first time that South Korea’s daily infections were above 30 in about a month.
The country has not used an app-based solution to trace potential contacts.
Instead, authorities have tracked people using a number of sources including mobile device tracking and financial transaction information to alert potential contacts.
Closer to home, Germany reports less than 180,000 confirmed cases, with an overall death toll of little more than 8,000, despite having a population of 83 million.
The country has been praised for enforcing social-distancing measures early in the pandemic and pursuing rigorous daily testing of the population.
Such large-scale testing enabled authorities to identify where the virus had spread and therefore contain any further infection.
Coronavirus: Everything you need to know