British Airways has launched a High Court action seeking damages from Spanish pilots’ association Sepla in move that risks escalating the turmoil at sister carrier Iberia.

BA and parent company International Airlines Group (IAG) lodged claims in the High Court in London on Friday seeking compensation for strikes by Iberia pilots late last year and early this.

The legal move came as aircraft engineers, baggage handlers and cabin crew at Iberia plan six days of strikes in an eight-day period before Christmas, starting on December 14.

The forthcoming strikes are in opposition to IAG plans to cut 4,500 jobs at Iberia – one in four of the workforce. IAG has set a deadline of January 31 for unions to agree to the cuts.

Pilots’ union Sepla is barred from joining the strikes following a settlement to the earlier dispute imposed by the Spanish government.

The pilots’ strikes followed Iberia’s establishment of budget operation Iberia Express using flight crew employed on different contracts and lower wages.

BA claims it suffered losses as a result of the strikes by pilots last December and in January. It is seeking damages against both Sepla and the International Federation of Airline Pilots Associations.

In a statement, IAG said: “The claim is made under European law which provides that airline groups should be free to establish air services across Europe.

“IAG is seeking a declaration that its EU rights were infringed and BA is seeking damages because the strikes affected its business, causing it to incur financial loss.”

A spokesman for Sepla said: “We are surprised that BA and IAG are taking this legal action eight months after the strike action.”

The union said it would refuse to negotiate with IAG on the restructuring of Iberia.

The head of one of six unions planning strikes this December said: “We are ready to negotiate salary cuts and increased productivity, but we don’t want sackings.”