The union Unite is expected to announce an escalation of strike action by Heathrow security officers in the next few days.

It’s thought new strikes were going to be announced on Friday, but it is now understood Unite will serve notice on Heathrow this week.

It’s been reported that 2,000 security officers based at Heathrow Terminal 5 and campus security are planning to hold 33 more strikes during the busy summer season, from 17 June until the end of August.

Heathrow said it has not yet received formal notice of Unite’s intention to strike, but a spokesperson said: “Passengers can rest assured that we will do everything we can to minimise strike disruption so they can enjoy their hard-earned summer holidays.

“Unite has already tried and failed to disrupt the airport with unnecessary strikes on some of our busiest days and we continue to build our plans to protect journeys during any future action.”

The spokesperson added talks will continue.