British Airways is pinning its hopes on a legal technicality to get a 12-day strike by cabin crew over Christmas called off. The company yesterday began legal action and is seeking an injunction from the courts to stop the strike taking place.

BA maintains that "irregularities" during the ballot of cabin crew by the Unite union render the strike illegal. Any irregularities were on a scale far too small to affect the outcome of the ballot but the airline hopes it can at least postpone industrial action until after Christmas.

A BA spokesman said the primary irregularity was that people who were no longer employed by the company had been balloted, which contravenes the law on union ballot. A High Court hearing on the action is set to take place today.

Willie Walsh, BA's chief executive, remained uncompromising yesterday in his resolve to face down the union and said: "We are absolutely determined to do whatever we can to protect our customers from this appalling, unjustified decision from Unite. We do not want to see a million Christmases ruined."

Unite announced the strikes on Monday after the ballot showed a 92 per cent majority in favour of industrial action in a turnout of 80 per cent of the union's 12,500 cabin crew members. The union is protesting at the imposition of changes to crew numbers as well as a pay freeze and plans to introduce different rates of pay and conditions for new crew members.

Derek Simpson and Tony Woodley, the joint general secretaries of Unite, offered a robust response to the airline after learning about the legal action. "If British Airways want to get Christmas back on schedule, and values its relations with its own core employees, it will now take up our offer – suspend the imposition of contractual changes and we will suspend the strike. That is the choice – a pause for peace or madhouse macho management."