British Airways cabin crew are set to stage 12 days of strikes over the Christmas holidays.

Unite union members voted massively in favour of strike action in a bitter row over jobs, pay and working conditions.

Strikes will run between December 22 and January 2, said sources.

The official ballot result will be announced later but sources told the Press Association that there had been an 80 per cent turnout, with a nine to one majority in favour of industrial action.

Strikes will cost the airline tens of millions of pounds every day, hitting flights at one of the busiest times of year for the industry.

The British Airlines Stewards and Stewardesses Association (Bassa) said it was conscious of the disruption action would cause to passengers going on holiday or visiting family and friends over Christmas.

But Bassa, a section of the Unite union, said cabin crew had been left with no choice by BA's management.

In a press release issued before a mass meeting of cabin crew at which the strike ballot result was being announced, Bassa criticised the airline for making cuts which it said would affect the quality of service to customers.

BA chief executive Willie Walsh has urged Unite members not to strike.

Hours before the meeting, BA announced that the deficits in its two pension schemes had grown from £2.1 billion in 2006 to £3.7 billion, an increase of 76%.