A traffic light system will be imposed, with a green watchlist to warn people if countries are dropping down a level.

A traffic light system that will categorise countries based on their COVID-19 risk levels is part of plans to safely restart foreign holidays.

The approach has been recommended by the government's Global Travel Taskforce, which has been working on how all international travel can resume since the publication of Boris Johnson's roadmap for lifting lockdown restrictions.

Under the prime minister's roadmap, foreign travel - apart from the limited current exemptions - will not be allowed any earlier than 17 May.

Here is how the traffic light system will work:

Green countries

• People arriving in the UK from "green list" countries will need to take a pre-departure test in that country

• On or before the second day after arriving in the UK, they will need to take a PCR test purchased from a private provider, which costs around £120

• They will not need to quarantine on their return unless they receive a positive test

• Test packages must be booked and paid for before travelling from a list of government-approved providers.

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Amber countries

• People arriving from "amber list" countries will have to quarantine for 10 days at home (day zero is the day you arrive)

• They will have to take a pre-departure test, then a PCR test on days two and eight, bought from a private provider

• Travellers will be given a unique reference number after buying the tests that they have to put on their passenger locator form before they travel to the UK

• There will be an option for "test to release" in which they can end self-isolation early if they test negative on day five, as well as day two, by purchasing an extra PCR test

• Test packages must be booked and paid for before travelling from a list of government-approved providers.

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Red countries

• Arrivals from the "red list" will have to quarantine for 10 days in a specific quarantine hotel at a cost of £1,750

• They will have to take a pre-departure test then PCR tests on day two and day eight

• Passengers must book and agree to pay for a quarantine package before departing for the UK.

Image:Countries will be placed on a green, amber or red list. File pic

Green watchlist

• This will identify countries most at risk of moving from green to amber so travellers have some warning

• However, the government "will not hesitate to act immediately should the data show that countries' risk ratings have changed".

How the list will be decided

• Countries in each category will be kept under review and the government will respond to data, focusing on variants of concern

• Vaccination rates, infection rates, the prevalence of variants, a country's genomic sequencing capacity and access to reliable scientific information will be taken into account

• The restrictions will be formally reviewed on 28 June to see whether the measures could be relaxed, followed by reviews "no later than 31 July and 1 October".