Test to Release is a scheme to allow travellers to be released from quarantine early after taking a COVID test when they return from a UK Gov AMBER country.  The test should be booked before the traveller arrives home and can be carried out at any of the Collinson test centres.  

More info on the scheme can be found here: https://www.gov.uk/guidance/coronavirus-covid-19-test-to-release-for-international-travel