LONDON — British Airways PLC cabin crew who were scheduled to work last weekend but who took strike action instead have been informed by the airline that they have lost their travel perks.

“Our cabin crew knew that if they took part in the strike they would lose their staff travel permanently,” BA said, adding that the airline had “made this clear” in January before the union’s strike ballot began, and reiterated it between the ballot result and the first strikes.

The perks include unlimited flights at 10% of the full fare plus taxes on standby tickets. After five years of service, staff are entitled to annual free tickets in business class.

“This is a noncontractual perk that the company can withdraw at its discretion,” BA said. “The industrial action impacted on our operation and our customers and we will, undoubtedly, suffer additional costs and further losses as a result.”

The first three-day strike cost BA about £21 million. A second strike, which will last four days, is scheduled to start March 27.

Unite, the union which represents cabin crew, condemned the move to remove perks, which many staff rely on to get to work following BA’s decision to close its regional bases and instead work out of London’s Heathrow Airport.

“This is the clearest possible example of BA’s bullying and contemptuous approach to its employees. Cabin crew showed last weekend that they will not be intimidated,” Unite said. The union said it will challenge this “vindictive move in whatever way seems appropriate.”

Separately, the British Airlines Pilots’ Association, or Balpa, said it will head to the European Court of Justice to resolve an issue over holiday pay with BA after the Supreme Court referred the matter to the European Union’s highest judicial authority.

“Had we won the test case against BA today our pilots would have gained up to £600 (about $900) each on the four weeks’ statutory holiday,” Balpa General Secretary Jim McAuslan said.

Balpa also has lodged employment tribunal cases against BA subsidiary Cityflyer; Virgin Atlantic Airways Ltd.; British Midland International, a unit of Deutsche Lufthansa AG; and easyJet PLC.

Pilots’ holiday pay is based on the Civil Aviation Working Time Regulations, rather than the EU’s Working Time Directive, which covers all other workers across other professions.

Under the working time regulations, workers’ annual leave holiday pay is the same as when they are working, but because the Civil Aviation regulation doesn’t provide a clear mechanism for calculating holiday pay, Balpa said many airlines have been “taking advantage of this loophole by paying holiday pay based on basic wages and not their flying pay or allowance they get for being away from home.” BA said it will await the decision from the European Court of Justice.

BA and unions have been battling for the past year over how to save the airline money. After failing to come to an agreement, BA on Nov. 16 took the step of reducing cabin crew on long-haul flights from London’s Heathrow to 14 employees from 15 without union support. Last month, the High Court ruled that those changes weren’t a breach of contract, meaning BA won’t be forced to reverse the changes or to pay damages to staff.