The union’s Unite regional co-ordinating officer, Wayne King, said: “There is deepening anger over pay among workers who are essential to the smooth running of Heathrow Airport”.
Heathrow urged the union to return to the bargaining table to resolve the pay dispute.
“We have proposed a progressive pay package giving at least a 4.6% pay rise to over 70% of our frontline colleagues. The total package offered is above RPI [Retail Prices Index] and is specifically designed to boost the wages of lower paid colleagues”.
As the dispute rumbles on, the airport said its contingency plans would ensure flights could still take off and land during one of the busiest period of the year.
“We will be working alongside our airline partners to minimise disruption caused to passengers as they look towards their well-deserved summer holidays,” it said.