Plans to impose a 14-day quarantine on international travellers arriving in the UK are “idiotic” and “unimplementable”, the chief executive of airline Ryanair has said.

Michael O’Leary claimed the proposals have “no medical or scientific basis”, and instead said face masks would “eliminate” the risk of spreading coronavirus.

Ryanair announced last week that it will operate nearly 1,000 flights per day from July 1 subject to European countries lifting flight restrictions and “effective public health measures” being put in place at airports.

Ministers have said international travellers will be asked to quarantine for 14 days when they enter the UK, either in accommodation of their choice or provided by the Government if there are no other options. An implementation date has not yet been announced.

Mr O’Leary told BBC Radio 4’s Today programme: “It’s laughable that this Government can come up with any plans for a quarantine that will be strict and fully enforced when already they are exempting the Irish, the French…

“It is idiotic and it’s unimplementable. You don’t have enough police in the UK to implement a two-week lockdown.

“And what’s really worrying is that a two-week lockdown has no medical or scientific basis to it in any event.

“If you really want to do something that’s effective – wear masks.”

Downing Street insisted there had never been an exemption for France, but said there would be an exemption for Ireland as part of the common travel area.

The Prime Minister’s spokesman also told a Westminster briefing on Monday afternoon that the quarantine would be reviewed every three weeks.

“Any changes brought in will be subject to a rolling review every three weeks to ensure they are in line with the latest scientific advice and that they remain effective and necessary,” he said.

The spokesman added: “The PM has said that those arriving in the UK from overseas will be required to self-isolate in order to prevent infections from abroad and a second wave of cases.

“The work on this is continuing and we will set out more details in due course.”

Culture Secretary Oliver Dowden earlier suggested the Government would legally enforce the quarantine rules, and said exemptions would be “very limited”.

He told Today: “We would look at the relevant enforcement mechanisms just as we have done with other measures.

“So for example, the measures that we took when we introduced the so-called lockdown – those were underpinned by regulations which had consequences in law, and I’m sure we’ll do the same thing.”