Ryanair passengers face even more disruption in the run up to Christmas after pilots in Portugal revealed they are joining next Wednesday's 24-hour strike announced by Irish-based pilots yesterday.

The Portuguese union, SPAC, said Ryanair's refusal to enter negotiations left it with no choice but to follow the lead of their Irish colleagues.

They said the strike action can be cancelled if Ryanair commits to serious negotiations.

The airline's pilots based in Italy are already due to strike for four hours this Friday, while the German union VC has also threatened as yet unspecified strike action.

Pilots in Dublin belonging to the Irish Airline Pilots' Association and the IMPACT trade union are to hold a one-day strike on Wednesday 20 December.

Pilots in Germany have also threatened as yet unspecified industrial action.

The Spanish pilots' union, SEPLA, has told Ryanair that it reserves the right to take legal action in pursuit of trade union rights.

In a letter to CEO Michael O'Leary, SEPLA said that its new company council within Ryanair has been set up in accordance with the applicable Spanish legislation.

As a result, it claims that Ryanair management's preferred Employee Representative Committee (ERC) system has no standing.

SEPLA urged Ryanair to recognise the company council.

It alleged that Ryanair's policy on trade unions constitutes a violation of the Fundamental Right to Freedom of Association in Article 28 of the Spanish constitution, adding that it reserves the right to take legal action in defence of this right.

The Spanish union wants Ryanair to immediately acknowledge that pilots providing services for the airline in Spain are workers subject to Spanish legislation and jurisdiction, and to regularise their contracts.

SEPLA says it is also advising unions who may represent other Ryanair grades, including cabin crew and ground staff, to claim their rights before various labour rights bodies in Spain.

It criticised Ryanair for its staff recruitment policies, including hiring pilots through brokers, as self-employed, or other intermediary arrangements.

The letter is signed by seven Ryanair pilots who are council members of SEPLA.

Ryanair management has written to pilots at its Italian bases ahead of their planned stoppage on Friday reiterating the consequences of striking, including the loss of pay rises, promotions and transfers.

Meanwhile, Ryanair today announced extra flights on 40 different routes from Cork, Dublin, Knock and Shannon airports for its summer 2018 schedule.

The airline said it will put an extra 250,000 seats on flights to destinations including Croatia, France, Italy, Lithuania, Malta, Poland, Portugal and Spain.