The head of Europe's largest budget airline Ryanair on Monday slammed the UK's new quarantine rules which came into effect requiring all people arriving in the country to self-isolate for 14 days, saying they were a "political stunt".
Michael O'Leary told the BBC: "You could be in Sainsbury's, you could be on the beach, you could be on the golf course in the unlikely event the Home Office calls you - all they will have is a mobile number."
He claimed even the Home Office acknowledged the rules were unenforceable.
Some industries have warned they will be severely impacted by the rules, and O'Leary warned of devastation.
But British Home Secretary Priti Patel has said the laws were designed "to prevent a second wave" of coronavirus, adding the measures were "proportionate" and being implemented "at the right time".
Under the new rules, those arriving in the UK should drive their own car to their destination, where possible, and once at their destination they must not use public transport or taxis, the BBC reported.
They must not go to work, school, or public areas, or have visitors - except for essential support.
Those arriving in England and Northern Ireland could face a fine of 1 000 pounds (about R21 000) if they fail to self-isolate for the full 14 days, while they face a 480 pounds fine in Scotland.
The enforcement rules in Wales are not clear.
Anyone arriving from the Republic of Ireland, the Channel Islands or the Isle of Man does not have to complete a form or enter quarantine.
There were also exemptions for workers in some industries such as road haulage and medical professionals who are providing essential care.
Meanwhile, British Airways, EasyJet and Ryanair have written to Procurator-General Jonathan Jones, the government's most senior legal official - the first stage required when taking legal action against the government.
The airlines have said that they were prepared to ask for a judicial review into the government's travel quarantine rules.