Security staff at Heathrow Airport have announced an escalation of strike action, with walkouts to take place nearly every weekend from mid-June to the end of August.
Members of Unite are embroiled in a long-running dispute over pay which led to industrial action last month and Easter.
From 24 June, 31 days of strikes will take place by more than 2,000 security staff. Officers from Heathrow terminal 3 are joining the industrial action for the first time in the coming dates.
The workers will strike on:
• June 24, 25, 28, 29 and 30
• July 14-16, 21-24, and 28-31
• August 4-7, 11-14, 18-20 and 24-27
The strikes will coincide with the beginning of the school holidays and the August bank holiday.
Heathrow said similar strikes in recent weeks by campus security and staff in terminal five had not been disruptive.
The union said Heathrow security officers were the highest paid before the COVID-19 pandemic but are now paid between £5,000 and £6,000 less a year than counterparts at Stansted and Gatwick airports.
Heathrow has said this is untrue and that Unite is not using like-for-like comparisons with airports that require anti-social working hours and to be on shift seven days a week.