British Airways and union leaders met with a government-backed mediator on Thursday as they awaited a court ruling on the airline’s bid to stop a 12-day strike over the Christmas and New Year’s break by its cabin crew.

BA and the Unite labour union turned to the conciliation service Acas after reaching a deadlock in talks over disputed changes to pay and working conditions that led to the planned walkout on Tuesday.

The industrial action is threatening to ruin Christmas and New Year vacation plans for more than a million people after baggage handlers and check-in staff at Heathrow and Aberdeen airports also announced strikes.

The High Court is due to rule in the afternoon on BA’s filing for an emergency injunction to stop the cabin crew walkout, which the airline argues is illegal because Unite’s strike ballot of around 13,000 workers included some 800 members who had taken voluntary redundancy packages.

The airline’s lawyer, Bruce Carr, told the court on Wednesday that the union was showing “withering contempt for the interests and concerns of over a million passengers.”

Mr. Carr said that around 800 members who had taken voluntary redundancy packages from BA were included in the ballot, rendering the vote invalid.

Unite has said that the ballot was undertaken in good faith and that the result reflected strong support for the strike. It noted an 80 percent turnout for the ballot, which resulted in a 92.5 percent “yes” vote.

If an injunction is granted by Justice Laura Cox, the union could hold another strike ballot, but would have to give several days notice of rescheduled strike action.

But there are some signs of unhappiness among BA staff who voted for the walkout as the public backlash grows.

“Twelve days over the Christmas period was a step too far. I certainly wasn’t aware that in voting to strike it would be 12 days and I have to say I was shocked,” one worker wrote on a chat site for members of the British Airlines Stewards and Stewardesses Association, a section of Unite.

The BA walkout would likely ground most of BA’s planes at a time it normally operates 650 flights and carries 90,000 passengers each day.

While angry BA passengers await the court’s decision, other festive season travellers were also hoping for a breakthrough in disputes that have resulted in planned walkouts by Eurostar train drivers and ground staff at Heathrow and Aberdeen airports.

But planned walkouts by baggage handlers and check-in staff employed by SAS Ground Services at London’s Heathrow and Aberdeen airports in a trio of 48-hour strikes — the first also starting on Tuesday — would have a much larger impact.

Unite, which is also representing the ground staff, has said it is willing to call off both the BA and SAS strikes if the employers agree to suspend the changes to pay and other working conditions.

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