The NHS has introduced a test and trace schemes to help the UK lift lockdown measures and stop the spread of coronavirus.
Thousands of contact tracers have been recruited to notify people - by email, text or by phone - if they've come into contact with someone with Covid-19.
Wales launched their system on 1 June and England, Scotland and Northern Ireland have systems up and running.
The UK's test and trace app is currently being trialled on the Isle of Wight but isn't ready yet to be rolled out elsewhere.
BBC Health and Science correspondent, Laura Foster, explains what is meant by track and trace, how it works and how it can keep the R number low.
UK Health leaders are calling for an urgent review to determine whether the country is properly prepared for a second wave of coronavirus. Elsewhere, local outbreaks have been reported in Germany, New Zealand and China - but experts say it's not the second wave.
#BBCOS #BBCOutsideSource Health Secretary Matt Hancock and the head of NHS Test and Trace explain how the programme is going to work, starting in England at 9am on 28 May.
Anyone who develops one or more COVID-19 symptoms will need to self-isolate and order a free test at nhs.uk/coronavirus or by calling 199.
People who test positive will be contacted by someone from NHS Test and Trace, who will establish who they have been in contact with and get in touch with those contacts to tell them to self-isolate.
Mr Hancock said the measures will be "voluntary" and a matter of "civic duty" - but that they will be made mandatory if necessary. What is SpaceX? How does it make money?
The company is set to make history as, alongside Nasa, it sends two astronauts to the International Space Station - the first time a private company has done this.
The launch from the Kennedy Space Center in Florida is scheduled for 16:33 local time (20:33 GMT / 21:33 BST).
Science correspondent Laura Foster takes a closer look at the company's aims. Is Antifa a ‘terrorist organization,' as US President Donald Trump claims, or a mere resistance movement trying to fight fascism? In this episode of Unpacked, we walk you through Antifa's story from Nazi Germany to present day America.
Antifa, which is short for anti-fascist, is not a unified organisation, but a loose term used to describe far-left activists who oppose anyone they see as holding facist views.
Antifa wants to stop the far right, white supremacists, homophobes, xenophobes and racists, from having any presence in society, from trying to embed themselves in communities and spreading their ideas as common sense and grow their political power.
In addition to that, Antifa activists tend to be opposed to the values of capitalism.
Groups that identify with the Antifa label are most commonly found in Europe and North America.
But anonymity along with a lack of structure, and overlap in ideas with other leftist groups makes it hard to know exactly how many people count themselves as Antifa members.
Antifascism is more of a counter movement, Because antifascism is a social movement, but it's specifically oriented towards opposing another movement .
Antifa groups also share a common set of tactics to achieve their goals. They conduct research, organize information campaigns and demonstrations to counter far-right street presence.