If they go ahead with the walk-out it will shut down the airport. More than 80% of staff, including firefighters, engineers, airside safety and air traffic control staff, have backed a ballot calling for industrial action.

They had been balloted by the GMB and Unite unions who refused to accept a deal from airport management that would have been worth 3.8% backdated to April, rising to 4%, back-dated from the beginning of October.

The unions, angry a deal should have been sorted in April, want at least a 5% rise and a strike is now on the cards. If it goes ahead the airport would be forced to close because of a lack of fire and safety cover.

Today airport bosses said they were “disappointed” the deal had been rejected but are still hoping industrial action can be averted through further talks.

Neil Pakey, the airport’s managing director, said: “Despite having held lengthy and productive meetings with employees, the company is naturally disappointed that our latest pay award and improved conditions continues to be rejected.

“Importantly however, the desire to resolve this dispute is naturally stronger than ever and I remain confident that further talks due to take place soon will see continued progress being made.”

Despite the ballot result, union chiefs confirmed dialogue would continue.

In a joint statement, Eddie Parker, GMB regional organiser and Carol Devereux, UNITE regional organiser added: “There is no doubt that lengthy talks that the Airport Company has undertaken with unions are helping to resolve this dispute.

“However we need to address the outstanding issues.”