UK nationals and residents returning to England from "red list" countries will be forced to quarantine for 10 days in government-approved accommodation such as hotels.
Meanwhile, foreign nationals from 33 red list countries where new variants have been identified - including South Africa, Portugal and South American nations - are banned from entering England altogether.
Wales is following the same policy as England, but Scotland has gone further by extending hotel quarantine to all international arrivals, red list or not.
Mandatory hotel quarantine for arrivals have already been introduced by other countries, including Australia, China and New Zealand.
Here's everything you need to know about the current travel rules for UK arrivals:
Who is allowed to travel abroad?
Owing to the national lockdown, people can only travel abroad for essential reasons. These can be: to do work that cannot be done from home, medical appointments and educational reasons. You cannot travel for a holiday.
You must also consider the rules in the country you are visiting. The government has compiled these rules here.
What do travellers arriving in the UK need?
Evidence of a negative Covid-19 test
Both UK and foreign nationals arriving from any country must provide evidence of a negative Covid-19 test result, taken up to three days before departure. Some people are exempt from this rule, e.g. aircraft pilots and crew, and border security staff.
Provide journey and contact details
Before heading to the airport, travellers have to provide their journey and contact details via an online passenger locator form. They must then ensure they have a copy of their completed form at border control - this can be a digital or hard copy.
Anyone who lies on a locator form to hide they have been to a red-list country within ten days before arriving faces up to ten years in jail if caught.
Self isolate for 10 days
Even with a negative test, travellers must self-isolate for 10 days after arriving in the UK, unless they have come from Ireland or they are exempt from doing so.
Passengers returning from a non-red list country, must quarantine for 10 days at home and complete two Covid-19 tests ont he second and eighth day after arriving.
Anyone arriving in England and Wales who has been in or through a red list country in the past 10 days must quarantine in government-approved accommodation, usually hotels. In Scotland, the hotel quarantine rules apply to all arrivals.
Paul Brand in January looked at what quarantine hotels would look like. Full story here
How will the hotel quarantine work, including costs?Bookings will be made through a dedicated online portal here.
People quarantining in hotels must pay £1,750 before they arrive, which covers the cost of the hotel stay, transport to the hotel, and coronavirus tests. An additional £650 will be charged for anyone over the age of 12, and £325 for children aged five to 12. There are no additonal fees for children under five.
People who fail to book a quarantine page will face a fine of up to £4,000, and they still have to pay for one on arrival. And failure follow hotel quarantine rules can result in a fine of up to £10,000.
Those booked into a quarantine hotel can only fly into Heathrow, Gatwick, London City, Birmingham and Farnborough airports. Those with pre-existing bookings to a different airport must change it. People who fail to do this could face a fine of up to £10,000.
Hotel guests will also need to take a Covid-19 test on or before day two of their stay, followed by another on or after day eight. Anyone who fails to take their first test faces a £1,000 fine, a £2,000 fine for failing to take the second test, as well as their quarantine period extending to 14 days.
What happens if travellers test positive during quarantine?
Those who test positive during the quarantine period, must remain in quarantine until they have received a negative test, and quarantined 10 days after that negative test.
If travellers develop coronavirus symptoms on day 9 or 10, even with a negative test on day 8, they must take another test. If the test is positive, their quarantine will be extended for another 10 days.
What are the countries in the 'red list' for England and Wales?
People returning from 33 countries must stay in specific accommodation for 10 days. They are:
Democratic Republic of Congo
Portugal (including Madeira and the Azores)
United Arab Emirates (UAE)
How will the rules be enforced?
All passengers should expect to be checked they are complying with all rules at various points throughout their journey, including by carriers at the time of departure , by airport staff throughout their journey and by Border Force officers on arrival.
There will also be spot checks by police, where appropriate, for those quarantining at home.
There will be a security presence throughout, with personnel directing travellers on arrival, in transit and on arrival at the hotels.
Security will also be present to ensure passengers remain at their facility and, where necessary, police will be called upon to provide additional support.
How many quarantine hotels are there?
The Government has struck deals with 16 hotels so far, providing 4,963 rooms for the new quarantine system, with a further 58,000 rooms currently on standby.
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