Security staff at Heathrow airport are to strike on eight days next month in a dispute over pay. The action by members of the Unite union will take place on 4, 5, 6, 9, 10, 25, 26 and 27 May, and follow strikes over Easter. Unite said the action next month would cause “inevitable disruption and delays” at a time when people were expected to be travelling to the UK for King Charles’s coronation. The 1,400 security officers involved in the dispute took 10 days of action from 31 March. Heathrow said it had been engaged in talks with Unite for months. The airport has offered a 10% pay increase since January, but in talks last week it said it had improved that with a further £1,150 lump sum this year. The airport said Unite was refusing to put the revised offer to its members. The dispute involves security guards based at Terminal 5. Other Unite members have voted against strikes, Heathrow said. Wayne King, a regional officer at Unite, said: “Strikes next month will cause further disruption to airport passengers but this dispute is a direct result of Heathrow’s stubborn refusal to make an offer that meets our members’ expectations. “Our members have been crystal clear they are seeking a substantial permanent increase in pay. A small one-off lump sum payment will not alleviate the financial pressures our members are facing on a daily basis.” Sharon Graham, the Unite general secretary, said: “This dispute is bound to escalate, with more workers being balloted and disruption set to continue throughout the summer.” A spokesperson for the airport said: “We kept Heathrow running smoothly during the first 10 days of Unite’s failed industrial action, and passengers can have confidence that we will do so again this time. We will not let Unite disrupt the flow of visitors to the UK during such an important period for the country. “Instead of chasing headlines, Unite should listen to its members. The majority of Heathrow colleagues do not want to strike and want to accept the offer on the table. “Each day that Unite refuses to allow members to vote on the 10% pay increase and a £1,150 lump sum payment is a day that costs colleagues money they deserve now.”