British Airways cabin crew will walk out for seven days this month after talks between the airline and unions broke down, in a dispute that analysts say could cost the airline around GBP£140 million pounds ($212.4 million).
The Unite union on Friday said BA cabin crew would strike for three days from March 20 and for four days from March 27, adding that BA had made a new formal offer to staff on Thursday which it would put to its members.
"BA made a formal offer to staff, which we are not recommending, but we will put that to members and should have a result on it by next week," Len McCluskey, Unite's assistant general secretary said at a press conference.
Cabin crew will not strike over the Easter holidays, which are spread across the first week of April, but Unite said if no deal is reached more strikes could be called after Easter.
BA said is was "extremely disappointed" and that proposals put forward by Unite fell "significantly short" of helping it reach its GBP£60 million cost-saving target.
"The strike could still be averted. Lufthansa had a one day strike last month but sorted it out, which shows what can be done," said Davy Stockbrokers analyst Stephen Furlong.
"This will probably cost BA something in the region of GBP£20 million a day but maybe less since they have some contingency plans in place," said Davy Stockbrokers aviation analyst Stephen Furlong.
BA has trained staff from other areas of the company to fill-in as cabin crew during the strike and has said it will hire 23 fully-crewed planes from charter companies to help run flights from Heathrow.
BA chief executive Willie Walsh has said the airline must move away from its old, inefficient ways if long-term survival is to be ensured, and that changes at the airline, which analysts believe is losing around GBP£1.5 million a day, are essential to help repair its precarious finances.
Earlier on Friday Gavin Halliday, BA's European head, said the strike threat had not hit bookings too badly.
"The damage the strike threat has done to our business is not as big as it could have been," Halliday said, adding the impact on earnings was likely "not disastrous".
The union's 13,000 cabin crew members have twice voted for industrial action as part of a dispute over job losses and changes to working practices, but a 12-day Christmas strike was halted following a successful legal challenge from BA.