From 04:00 GMT this morning (18 January), people travelling to the UK will have to show proof of a negative Covid-19 test before setting off. This may be taken up to three days before their journey begins.
The Government says it will accept any test with at least 97% specificity and 80% sensitivity.
Exempt from the scheme are Children under 11, passengers from the Common Travel Area (the Republic of Ireland, Channel Islands or the Isle of Man), travellers from the Falkland Islands, Ascension Islands and St Helena, hauliers, crews (air, international rail and maritime) and a specific list.
If you are on holiday in St Lucia, Barbados, Antigua and Barbuda arriving in the UK before 21 January.
Coronavirus (Covid-19): jobs that qualify for travel exemptions
Even with the new testing requirements, travellers – including British nationals – must still self-isolate for 10 days on arrival.
People arriving in England from some countries can reduce their quarantine period by paying for a private Covid test. The test must be booked by travellers before their journey, and it can only be taken after five full days of self-isolation. Tests cost between £65 and £120, and results are normally received within 24 to 48 hours. People who test negative can stop self-isolating once they have their result. Those who test positive must quarantine for another 10 days from the date of the test.
The Government has published a list of approved providers. Private providers of coronavirus testing: what you need to know