The city of Liverpool has been selected for the first pilot of whole city testing in England starting this week.
Everyone living or working in the area, home to half a million people, will be offered an assay whether they have symptoms or not.
The government is looking to control the spread of the virus in Liverpool, one of the cities with most infections in the country, to help local leaders in their decision making.
Residents and workers will be tested using a combination of existing swab tests and new lateral flow tests which can deliver results within an hour without being processed in a lab.
The project will also involve LAMP, a new type of technology that delivers significant volumes of tests, to be deployed in Liverpool University Hospitals NHS Foundation Trust for NHS staff.
Westminster is trialling this system to assess the speed and reliability of mass testing.
Eligible people will be able to book a test online, walk-up, or by invitation from the local authority.
They will be carried out in new and existing test sites, using home kits, in hospitals and care home settings, and schools, universities and workplaces.
Anyone who tests positive, using either a lateral flow test or an existing swab test, must self-isolate along with their household immediately and their contacts will be traced. Those who test negative will need to continue to follow all national guidance.