Union members who work for BA’s Mixed Fleet operation will stop work for two sets of three days, starting on Sunday 5 February and Thursday 9 February — a full week, apart from a break on the Wednesday.

Mixed Fleet cabin crew work on a range of domestic, European and long-haul routes from Heathrow.

So far this year there have been two previous strikes — one of two days, and one of three. The airline says it cancelled 68 flights over the five days, representing 1.7 per cent of the total departures. In addition, BA brought in aircraft from other airlines to cover for grounded flights.

Unite’s national officer, Oliver Richardson, said: “Rather than addressing poverty pay, British Airways is spending money hand over fist on chartering in aircraft to cover striking cabin crew.

“If it can afford to waste money in such a manner then British Airways can clearly afford to address pay levels which are among the lowest in the industry.”

A BA spokesperson said: “Our pay offer for Mixed Fleet crew is consistent with deals agreed with Unite for other British Airways colleagues.

“It also reflects pay awards given by other companies in the UK and will ensure that rewards for Mixed Fleet remain in line with those for cabin crew at our airline competitors.”

The airline will publish its plans for the first three days of strikes on Tuesday 31 January, and for the second tranche on Thursday 2 February. The spokesperson said: “We have flown all customers to their destinations during the previous strikes by Mixed Fleet Unite and we will ensure this happens again.”

Mr Richardson said: “We would urge British Airways to wake up to the determination of our members, who contribute massively to the billions of pounds in profits the airline generates, and get around the negotiating table to resolve the dispute and avoid a further six days of costly strike action.”