Ryanair has cancelled 12 UK domestic and international routes due to a disagreement with the UK Civil Aviation Authority (CAA).

The low-cost carrier said the CAA had introduced new regulations around wet leasing aircraft ahead of the end of the Brexit transition, causing “unnecessary loss of connectivity to the UK economy”.

The aviation authority disputed the claim.

Ryanair said CAA director, David Kendrick, had “inexplicably” introduced the new regulatory barriers.

A Ryanair spokesperson added: “We are disappointed to have to cancel 12 UK domestic and international – to Morocco and Ukraine - routes from London, Manchester, Liverpool, Edinburgh, Belfast and Derry, because of the unexpected policy-shift.

“Ryanair UK had agreed Brexit contingency arrangements with the CAA two years ago and cannot comply with its new and impractical requirements.”

In a statement published on its website, Paul Smith argued the CAA was not to blame.

“It is incorrect for the airline to state that the UK Civil Aviation Authority has changed its wet-leasing policy at short notice.”

Wet-leasing involves an aircraft being leased along with crew, maintenance and insurance.

“It has been our long-standing position that a UK airline with a significant presence in the UK, such as Ryanair UK does, should not rely heavily on using wet-leased, foreign-registered aircraft to undertake their operations,” the statement continued.

“Doing so undermines the competitiveness of the UK aviation industry and the effectiveness of the regulatory regime.

“This is a view shared by regulators around the world and has nothing to do with our preparations for the end of the transition period.

“The decision to cancel these flights was taken by Ryanair alone.

“We will continue to engage with the airline on these matter as we seek to act in the best interest of consumers.”

The CAA said Ryanair has one aircraft, of its more than 470, listed on the register in the UK.