A Ryanair plane at Dublin airport. Paul Faith/AFP/Getty Images

Ryanair has revealed it is prepared to recognise pilot unions, as it seeks to avoid a series of strikes that could wreak havoc on its Christmas schedule.

The move marks a major milestone for the Irish carrier, which had steadfastly refused to recognise unions up until now as it was entitled under law not to recognise unions in its workplace.

However, with the threat of its first ever pilot strike hanging over its head, the airline has written to pilot unions in Ireland, the UK, Germany, Italy, Spain and Portugal inviting them for talks.

"Ryanair will now change its long standing policy of not recognising unions in order to avoid any threat of disruption to its customers and its flights from pilot unions during Christmas week," the statement said.

"Ryanair now calls on these pilot unions to call off the threatened industrial action on Wednesday (20 December) so that our customers can look forward to travelling home for Christmas without the threat or worry of pilot strikes hanging over them."

Last week, Italian union ANPAC announced plans for its members to take industrial action on 15 December between 2pm GMT and 6pm GMT. Meanwhile, Germany-based Cockpit union said Tuesday (12 December) that walkouts would be expected "any time starting immediately" but didn't give any specific timing.

Ryanair pilots in Portugal and Ireland, meanwhile, were due to stage a 24-hour walkout on 20 December, a measure which was also mooted by their Spanish counterparts.

Michael O'Leary, the airline's chief executive, said the decision to recognise unions had been taken to ensure flights over the Christmas period would go ahead as planned.

"We wish to remove any worry or concern that they may be disrupted by pilot industrial action next week," he said on Friday (15 December).

"If the best way to achieve this is to talk to our pilots through a recognised union process, then we are prepared to do so, and we have written today to these unions inviting them to talks to recognise them and calling on them to cancel the threatened industrial action planned for Christmas week," he added.

"Recognising unions will be a significant change for Ryanair, but we have delivered radical change before."