British Airways cabin crew will strike for seven days later this month in the run-up to the busy Easter holidays after talks over pay broke down, trade union Unite announced.
The news could spark travel misery for millions of BA travellers with the prospect of more industrial action next month if the long-running dispute over pay and working conditions is not resolved.
Unite, Britain's biggest union, said in a statement that staff would spread the stoppages between March 20 and March 30 and warned that further walkouts may occur in mid-April after Easter.
Loss-making BA, which is slashing costs to save cash, had already won a legal battle in December to prevent a 12-day walkout by cabin crew over Christmas and New Year after a judge ruled that a staff ballot was invalid.
"Strikes are planned for March 20, 21 and 22 and further on March 27, 28, 29 and 30," senior Unite official Len McCluskey said in a statement on Friday.
"There will be no strikes over the Easter period, as we already promised, but further industrial action will be called to take place after April 14 if the dispute has not been resolved," added McCluskey, Unite's assistant general secretary.
BA slammed Unite's announcement which it said would cause massive disruption to travellers in the run-up to Easter, which takes place at the start of April.
"British Airways is extremely disappointed that Unite has announced plans for massive disruption for hundreds of thousands of our customers in the run-up to the Easter holidays," BA said in a separate statement.
"Unite's action has no shred of justification," added the carrier.
Unite is protesting at BA's imposed contractual changes that include fewer cabin crew on flights, a pay freeze and different working conditions for new members of staff.
"British Airways is facing two years of record financial losses," BA continued.
"Unlike other businesses, we have avoided compulsory redundancies and made changes designed to secure a long-term future for our company and our staff."
A BA spokesman said that a revised flights timetable would be announced prior to the strikes, and stressed that the company would be "available" for fresh talks with the Unite union at "any time".
Last month, struggling BA forecast a record loss in its current financial year owing to weak demand for air travel and despite sharp cost cutting.
BA made the admission in a third-quarter results statement which also revealed that pre-tax losses stood at a better-than-expected 50 million pounds (57 million euros, 79 million dollars) in the three months to December.
That compared with a pre-tax loss of 122 million pounds in the same period of 2008 and easily beat market expectations for a loss of 150 million pounds.