Update 11 May: The UK government has now clarified that the quarantine period for international travellers will be 14 days, with passengers required to provide the accommodation and contact details of where they will self-isolate. They will also be encouraged to download and use the NHS contact tracing app currently in a trial period on the Isle of Wight. These measures will not come into force on 13 May along with the removal of some lockdown restrictions. Instead, a detailed plan for the introduction of measures, including a list of exemptions to the rule, will be released "shortly".

IAG chief executive Willie Walsh has hit out at the announcement, telling the Transport Select Committee the measure is "definitely going to make it worse" for airlines. He said: "There's nothing promising in anything I heard the prime minister say yesterday. We had been planning to resume, on a pretty significant basis, flying in July, but I think we'll have to review that... Despite the fact that there were some rumours about the quarantine, I don't think anybody believed that the UK government would actually implement it if they were serious about getting the economy moving again."

He also questioned why the measure will only apply to passengers arriving by air and not train or boat. "I don't understand that, but maybe the prime minister will be able to clarify the science behind it." He also said the decision to not impose a quarantine on travellers from France "doesn't make sense".

Update 19 May:?The UK government is planning to begin implementing its mandatory 14-day quarantine period for international air travellers in early June, with details to be released soon, according to transport secretary Grant Shapps.

Speaking in the Commons yesterday, Shapps hinted that initially the measure will be a ¡°blanket solution¡±, though countries with a low infection rate could be exempted from the rules in the future.

A spokesman for the prime minister has also backtracked the earlier announcement that France will be exempt from the rule, saying the statement referred to the need for cooperation to manage the countries¡¯ common border.?

UK prime minister Boris Johnson last night said ¡°it will soon be the time¡± to impose a quarantine period for people flying into the country. Exact details have yet to be released, but the government has confirmed the measure will not apply to travellers coming from France.

Addressing the nation on Sunday to outline the government¡¯s approach to easing lockdown restrictions, Johnson said: ¡°¡­to prevent reinfection from abroad, I am serving notice that it will soon be the time ¨C with transmission significantly lower ¨C to impose quarantine on people coming into this country by air.¡±

He said the measure will be made more effective by the fact that the rate of transmission ¨C or R-0 value ¨C in the UK is now below zero.

Following the speech, the UK and French governments released a joint statement saying they would "work together in taking forward appropriate border measures", with no quarantine to be imposed on travellers arriving from France and vice versa.?

British airlines last week said they were told to prepare for inbound passengers to be subject to a 14-day self-isolation period on arrival into the country. Airlines UK said the move would ¡°effectively kill¡± international travel for the country and cause damage to the economy.

But airline and airport bosses told the BBC following the announcement that they still have not been told even basic details, such as when the measure will go into effect, when it will end, or whether it will be reviewed on a regular basis.

Airlines UK chief executive Tim Alderslade again called for the government to support the aviation industry through the expected continuation of low passenger demand in the wake of the quarantine announcement, such as an extension of the job retention scheme to October and holidays on payments of Air Passenger Duty and charges such as air traffic control and Civil Aviation Authority.

¡°Public health must of course be the priority and we respect Sage [Scientific Advisory Group for Emergencies] advice. We all ¨C including government ¨C need to adapt to the new normal but closing off air travel in this way is not the way to achieve this. Ministers are effectively telling people they can no longer travel for the foreseeable future and airlines will respond to that by grounding their operations ¨C and that is why they require urgent additional government support to get through this growing crisis.¡±

The announcement comes after IATA said global air passenger demand had fallen to its lowest level since 2006 in March. By its latest estimates, IATA predicts the coronavirus crisis will cost airlines US$314 billion in passenger revenue in 2020 alone.

The impact of the virus has led some airlines operating in the UK to announce job cuts, including up to 12,000 redundancies at British Airways, 3,000 at Virgin Atlantic and 3,000 at Ryanair. Virgin Atlantic has said it will not restart operations at Gatwick once restrictions are lifted, while BA has also warned it might not return to the London airport.