British Airways cabin crew are to stage a two-week strike from 1 July, the Unite union has said, in a long-running dispute over pay and benefits.
Unite said BA had refused to accept its final offer on the issue of the "sanctioning" of striking cabin crew.
The union claims that crew who previously walked out have not had their bonuses or benefits, including free and discounted travel, restored.
BA said that the proposed action was "extreme and completely unnecessary".
Unite said it would "vigorously" pursue legal action against BA on behalf of the 1,400 cabin crew affected.
The union claims that British Airways has formed a "blacklist to impose sanctions on striking cabin crew", which has led to bonus payments being cut and the removal of staff travel concessions.
Unite had originally planned a four-day strike to start on Friday, but this was suspended while the two sides tried to resolve the dispute.
However, the union has now said its members among BA's mixed fleet crew will go on strike from 00:01 on Saturday 1 July to 23:59 on Sunday 16 July.
BA reassured passengers that it would continue to fly all customers to their destinations.
The airline said: "We had reached a deal on pay, which Unite agreed was acceptable. Unite has already confirmed it is pursuing the non-pay issues in this dispute through the courts.
"We urge Unite to let its members vote on the pay proposals."
Unite assistant general secretary Howard Beckett said: "The refusal by British Airways bosses to meaningfully consider our compromise offer is deeply disappointing.
"A resolution to this long-running dispute was within the grasp of British Airways, but instead of grabbing that opportunity, bosses rebuffed it. It now means British Airways faces an entirely avoidable two-week strike and prolonged legal action on behalf of over 1,400 mixed cabin crew."
There have been 26 days of strike action by BA staff since the start of the year.