Unite union general secretary Len McCluskey has written to BA chief executive Alex Cruz, railing against what he branded the airline’s "fire and rehire" plans.

In late-April, BA parent IAG announced plans to cut up to 12,000 roles as part of a "restructuring and redundancy" programme, weeks after coming to terms with Unite over a bespoke furlough arrangement for tens of thousands of BA staff.

Unite and BA have been locked in talks for several weeks, with Unite claiming staff have been told they face being handed their notice and having to reapply for their old role, or a similar role, on new terms – and at a lower rate of pay.

BA reportedly started serving notice to some employees on this basis earlier this month.

In his letter, seen by the BBC, McCluskey said the union would work "every hour" between now and 7 August when BA is reportedly due to enact the next phase of its plan to convince the carrier’s bosses to change course.

"You can take this letter as our commitment to do that," said McCluskey. "However, you can also take this as an intention to defend our members by moving towards industrial action with immediate effect."

It comes after pilots union Balpa last week reluctantly recommended its members accept a range of "job protection" measures agreed with BA after months of negotiations, which it said would nonetheless result in up to 270 redundancies.

A BA spokesperson said: "This is the biggest challenge the airline and our industry has ever faced. Sadly, the global pandemic has resulted in job losses across every industry. Many airlines have already made thousands of staff redundant.

"We are not immune to this crisis. We have to adapt to survive, so we will continue with the proper, lawful consultative process and we will keep inviting union representatives to discuss our proposals to the serious challenges we face.

"It is not too late to find solutions – as we have done with Balpa – and to protect jobs.​"