British Airways is facing the threat of a fresh wave of strikes by its cabin crew after staff voted heavily in favour of more walkouts in their bitter dispute with the airline.
Unite said its members voted by 5,751 to 1,579 to take further industrial action following 22 days of strikes last year which cost the airline more than 150m.
The union pulled back from naming dates and must give seven days' notice of any action.
Unite's new leader, Len McCluskey, said: "For the fourth time in 13 months, British Airways cabin crew have voted overwhelmingly in support of their union and expressed their dissatisfaction with management behaviour. Indeed, the turnout and the majority on this occasion are much greater than in the last ballot.
"Surely BA management must now wake up and listen to the voice of their skilled and dedicated employees."
The figures were revealed as the company completed its merger with Spanish carrier Iberia to create a new holding company, International Consolidated Airlines Group (IAG).
The dispute started more than a year ago over cost-cutting but now centres on the removal of travel concessions from workers who went on strike, and disciplinary action taken against Unite members.
Unite said the turnout in the ballot was 75 per cent, while the majority of those voting for industrial action was 78.5 per cent.
The union balloted 10,220 cabin crew staff, 7,330 of whom returned valid papers.
BA has pledged to run a full long haul service if there are any fresh strikes and there was little suggestion it would renegotiate the deal at the heart of the dispute.
A BA spokesman said: "Tony Woodley shook hands on this deal in October. Unite said it would recommend it to members, but then reneged on its promise."