British Airways' parent company has commenced legal action against the implementation of a 14-day quarantine on international arrivals, a ruling that has been described as "catastrophic" for the hospitality and tourism sectors.
The airline's challenge, which accuses the government of "unfair" exemptions for some travellers and "disproportionate" restrictions on visitors, has the support of budget carriers Ryanair and EasyJet.
British Airway's owner International Airlines Group (IAG) has sent a legal letter to the Home Office which is understood to expose loopholes that allow business travellers who commute weekly from the UK to the EU to avoid self-isolation.
This contrasts with blanket quarantine measures for nearly all other travellers, irrespective of where they have come from.
IAG's legal case is also expected to claim the quarantine restrictions are unjustified in that they are stricter than those placed on people in the UK suffering from Covid-19, who are asked to self-isolate for seven days and will not face fines of up to £1,000.
The measures come into effect today (8 June) and will be reviewed in three weeks' time, when ‘travel corridors' may be introduced to allow travel to certain countries.
Opposition is also mounting from a travel and hospitality industry collective of more than 500 businesses, called Quash Quarantine, which is urging for options including a judicial review or seeking an injunction.
George Morgan-Grenville, chief executive of tour operator Red Savannah and leader of Quash Quarantine, said: "There are more holes than in a sieve in this unworkable, poorly-thought through and economically damaging government policy.
"The government has rushed through these measures,with no scientific evidence supported by its Sage advisory group and no consultation with the travel companies that matter.
"We are taking soundings and discussing our next move. We are watching the BA legal action with keen interest."
By Ben Ireland and Phil Davies