British Airways (BA) has warned cabin crew it will axe benefits and travel perks to striking staff.

According to reports, a BA spokeswoman confirmed the airline has written to its 13,400 cabin crew ahead of the strike ballot that opens on Monday to warn that taking industrial action would mean the end to benefits such as free and discounted air fares.

A BA spokeswoman said: “As a responsible employer and in view of Unite’s apparent wish for a lengthy strike, we have written to crew individually  to set out the consequences of different ballot outcomes.”

In a letter Bill Francis, the BA executive in charge of cabin crew,  admitted that the failed Christmas walkout cost the airline “millions of pounds” in lost revenue as passengers booked elsewhere.

In the letter he said: “We cannot go on like this. In December we saw what our customers and the wider public thought about a strike. Their patience is running out. It is time to be absolutely clear about what will happen if a strike takes place.”

Unite assistant general secretary Len McCluskey said the warning on staff travel perks was an act of “pettiness”.