British Airways will take Unite union to court to seek an injunction against strikes by cabin crew which are due to start on 22 December.
The airline will challenge the validity of Unite's ballot which returned a vote in favour of strikes. It alleges the ballot included staff who are no longer employed by the company.
A spokesman for British Airways told Personnel Today: "We will be seeking an injunction to prevent Unite going ahead with the strike.
"BA believe that for Unite to include in their ballot employees who are no longer employed at the airline is a breach of industrial law.
"We will take this to the High Court as soon as possible."
If BA is successful and gains the injunction Unite may be forced to re-ballot the airline's cabin crew for strikes.
The strike action is expected to see 12,500 cabin crew walk out for 12 days between 22 December and 2 January.
Unite said 80% of BA's cabin crew participated in the ballot and they voted 9:1 for a 12-day strike over Christmas.