The Unite union has confirmed it is preparing a fresh ballot of British Airways cabin crew that could extend strikes into July and August.

BA cabin crew will end their current bout of action at midnight tonight, after completing 15 days of strikes in the past 17 days, and the airline pledged to operate “the vast majority” of flights from tomorrow.

Disruption on Thursday and Friday is likely to be confined to short-haul flights to and from Heathrow, with a full service resumed from Saturday. A BA spokeswoman said: “We will operate all long-haul departures from Heathrow.”

Both sides continue to insist they are available for talks. However, there is no immediate settlement in sight, with the major sticking point remaining BA’s withdrawal of travel concessions to strikers.

A Unite spokesman said the new ballot would be “on travel concessions and other matters”, but would give no further details pending an announcement.

The union denied reports that cabin crew are divided over whether to continue the strikes. BA chief executive Willie Walsh earlier said he was prepared to maintain his strike-breaking operation “for as long as it takes” and pledged to operate 100% of services if strikes resumed.