Ten days of strike action by security staff at Heathrow Airport will begin Friday (March 31) after last-minute talks failed.
Negotiations between Unite and Heathrow continued into this evening but an agreement over pay was not reached.
The airport says its “contingency plans will keep the airport operating as normal throughout”.
The strikes affect workers in Terminal 5, which is used by British Airways and security staff checking cargo arriving at the airport, but there will be a knock-on effect.
BA has already cancelled flights in preparation for the action.
The strikes, involving more than 1,400 staff, are due to end on Easter Sunday.
Unite general secretary Sharon Graham said: “Heathrow can afford to pay a decent pay rise to its workers. This is a wealthy company which is about to return to bumper profits.
“In recent years it’s approved an astronomical rise in salary for its CEO and paid out dividends to shareholders worth billions.
“Yet somehow Heathrow executives seem to think it’s acceptable to offer what amounts to a real terms pay cut to its security guards and ground staff who are already on poverty pay.
“Unite has a laser-like focus on our members’ jobs, pay and conditions. The workforce at Heathrow Airport will receive the union’s unswerving support in this fight for a decent deal.”
A Heathrow spokesperson said: "We will not let these unnecessary strikes impact the hard-earned holidays of our passengers. Our contingency plans will keep the airport operating as normal throughout. We are deploying 1,000 additional colleagues and the entire management team who will be in the terminals providing assistance to passengers over the busy Easter getaway.
“We know that the majority of colleagues do not support strike action. Following further talks, Unite has again refused to take an improved offer to members, despite the PCS union wanting to do so. Colleagues could have an above inflation 10% pay increase back-dated to January 1 and a lump sum payment of £1,150, but instead they’re left empty-handed by Unite’s actions. The only reason Unite refuse to take the improved offer to members is because they fear they’ll back it."
Unite regional coordinating officer Wayne King said: “Heathrow Airport has thrown away the opportunity to avoid strikes. Unite went into today’s meeting looking for an offer our members could accept. Unfortunately it seems Heathrow Airports Ltd went in with no intention of avoiding industrial action.
“The strike action will undoubtedly result in severe delays and disruption to passengers across the airport but this dispute is a direct result of Heathrow Airport’s stubborn refusal to pay its workers fairly.”