Almost 3,000 cabin crew from British Airways’ mixed fleet branch at Heathrow will strike again next week in a row over what the union describes as poverty pay.

The crew will walk out for three days from next Thursday, following a 48-hour strike this week that led to about 100 flights being cancelled or merged by BA.

The union, Unite, says pay at the national carrier is so low that crew are taking second jobs or working while sick because they cannot afford to take a day off.

With more crew having joined up since the dispute started, Unite called on BA to raise pay, which starts at £12,192 basic, although the airline says most crew earn at least £21,000 with flying allowances.

Oliver Richardson, a national officer of the Unite union, said: “British Airways should be under no illusion about our members’ determination to secure a settlement that addresses their concerns over poverty pay.”

All new recruits to BA now join the mixed fleet, which was set up during the bitter industrial dispute of 2010-11 and work on long- and short-haul flights.

BA said the strike action was “bizarre and regrettable”. The airline said the last strike had failed to disrupt operations and added: “We will again aim to ensure that all our customers travel to their destinations.”