British Airways mixed fleet cabin crew are to stage a fresh round of strikes in a long-running dispute over pay.
Members of Unite will walk out for 14 days from July 19, just three days after completing a 16-day stoppage.
The union said the new action underlined the determination of its members to continue campaigning for a better pay deal.
National officer Oliver Richardson said: "Today's announcement of a further escalation, underlines the determination of our members in their fight for better pay and against British Airways' bullying behaviour.
"We are seeing strong support for the ongoing strike action.
"The time and money British Airways is spending on wet leasing aircraft and bullying striking cabin crew are resources which could easily settle this dispute.
"It's high time British Airways stopped spending millions defending low pay and its bullying approach by negotiating a settlement to this long running dispute."
Unite has launched legal action over BA's decision to lease aircraft from another airline during the strike.
The union said it was challenging the Government's go-ahead for the lease of nine aircraft from Qatar Airways during the current stoppage, which started last weekend.
The union staged a protest outside the London head office of Qatar Airways on the fifth day of strike action by its members in BA's mixed fleet.
Mr Richardson said: "The wet leasing of Qatar Airways' aircraft should not have been approved by the Government or been sought by British Airways.
"We believe it is not only in breach of European regulations and non-compliant with civil aviation safety, but has also driven a coach and horses through British Airways' own corporate social responsibility policy, which is not worth the paper it's written on.
"British Airways customers will be alarmed at Qatar Airways' record on sex discrimination and the lengths British Airways is going to try an undermine lawful strike action."
A BA spokesman said: "As during Unite's previous industrial action, we will ensure all our customers reach their destinations. In the current strike period, we are operating 99.5% of our normal schedule.
"Instead of calling further completely unnecessary strikes, Unite should allow its members a vote on the pay deal we reached two months ago.
"It seems extraordinary that a trade union should ask its members to give up their pay and benefits for virtually the whole of July, trying to target the holidays of hard-working families, rather than give those members a chance to settle the central issue of the dispute."