Further details on government plans to introduce a two-week quarantine period for people arriving in the UK are expected soon.
So what do we know so far?
Any passengers arriving in the UK by plane, ferry or train will have to provide an address where they will remain for two weeks.
The idea is to reduce the spread of coronavirus by minimising the contact international travellers have with other people when they first arrive.
The government has not given a starting date, but has said it wants the measures introduced “as soon as possible”.
On arrival, travellers will need to provide UK Border Force officials with an address where they will self-isolate. Otherwise, accommodation will be arranged by the government.
People travelling from the Republic of Ireland will not need to self-isolate.
Initially, it was suggested travellers from France were also exempt. However, the government later insisted the quarantine measures will also apply to them.
Transport Secretary Grant Shapps has said “air bridges” could be introduced. This would be an arrangement where travellers from countries with low coronavirus levels could be exempt from quarantine.
Speaking to the BBC, Greece’s tourism minister called for his country – which has not been badly affected – to be among them.
It is also expected that delivery workers, like lorry drivers, will not have to enter quarantine.
UK airlines fear the measures will have a devastating impact on their industry and the wider economy.
Michael O’Leary, chief executive of Ryanair, has said the policy had “no credibility” and has predicted it will be gone by June.
And Airlines UK, which represents various airlines, said quarantine “would effectively kill off air travel”.
The British Ports Association, which represents ferry companies, has also spoken out against the measures – calling them “overzealous”.
The government guidance says all flight passengers should remain at least 2m (6ft) apart from other people wherever possible and consider wearing a face covering.
People travelling through Manchester, Stansted and East Midlands airports have already been told to cover their faces and wear gloves.
EasyJet has said it plans to keep the middle seats on planes empty for a time. Emirates and the US airline Delta have announced similar plans.
However, the International Air Transport Association, which represents global airlines, says leaving the middle seat empty would not improve passenger safety. It also says most airlines would not have made money last year if a third of the seats had been removed.
Some temperature screening trials will also be conducted at Stansted. Heathrow, one of the world’s busiest airports, is already trialling large-scale temperature checks.
Air France says passengers will be temperature-checked before flying. The carrier has also made face masks compulsory – similar to several US airlines.
Since that advice was issued, far fewer people have been flying. For example, between 16 and 22 April, the number of air passengers coming into the UK was 99% lower than the same period in 2019.
Ryanair, for example, carried 40,000 passengers in April – down from 13.5 million in the same month last year. It expects passenger numbers to halve in the current financial year.
However, the airline still plans to reintroduce 40% of its flights from 1 July, subject to travel restrictions being lifted and safety measures being brought in at airports.
British Airways is reviewing its plans to run 50% of its schedule from July, because of new quarantine rules.