The carrier said more than 200,000 passengers would be lost from Cork, Shannon, Knock and Kerry.

The airline said the “defective quarantine restriction on EU visitors” was affecting sales just as the UK and Northern Ireland opened up air bridges to most EU countries.

Ireland accounts for less than 8% of Ryanair’s traffic, but the carrier argues tourism and connectivity for Irish workers commuting to and from the UK “is now suffering unrecoverable losses”, as arriving EU passengers are forced to quarantine, even though the border to Northern Ireland remains open with no restrictions.

A Ryanair spokesperson said: “Last week when the UK and Northern Ireland removed travel restrictions on short haul flights to and from the European Union, Ireland became the only country in the EU with a blanket 14-day quarantine restriction on all arrivals from EU countries, most of which have lower Covid case rates than Ireland.

“It makes no sense, when governments all over Europe have opened up EU flights since 1st June and removed travel restrictions on intra-EU travel, that the Irish government continues to treat countries like Germany, Denmark and Greece as if they were suffering similar levels of Covid as the USA, Brazil and India.”