EasyJet is to be sued by customers in Northern Ireland impacted by a major data breach, it emerged on Monday.
The airline is facing a group action at the High Court in Belfast for alleged violation of privacy rights.
Last week easyJet announced it had been the target of a "highly sophisticated cyber-attack".
Email addresses and travel details of nine million customers were exposed, with more than 2,200 also having their credit card details accessed.
The firm said it became aware of the hack in January, and has informed the UK's Information Commissioner's Office.
It stressed there is no evidence that any personal information has been misused.
But lawyers representing more than 50 customers in Northern Ireland have begun a group litigation against the airline.
Darragh Mackin of Belfast firm Phoenix Law confirmed their intention to seek damages for alleged breaches of privacy and data protection.
"This is probably the largest data breach in the history of this jurisdiction," the solicitor said.
"It is a mammoth data breach, and a gross failure of responsibility that has undoubtedly had a serious impact on our clients who have suffered considerable distress as a result."
Mr Mackin insisted easyJet was under an obligation to ensure all steps were taken to protect and store his clients' personal data.
"Regrettably, this mass data breach is an unrivalled failure of responsibility, and as such our clients have now no option but to proceed by way of litigation to recover compensation for the loss and damage they have sustained," he claimed.
"Our clients have now commenced litigation to ensure that Easyjet are held accountable for their failures, and that they are properly compensated for the loss in this instance."