The union threatening summer strike chaos at Heathrow says it will engage “constructively” and “positively” in talks tomorrow (Thursday) aimed at breaking the deadlock.

The conciliation service Acas is to host talks between the airport and Unite in a bid to resolve a pay dispute and averting strike action by more than 4,000 workers.

Security guards, engineers, passenger service operatives and passenger service drivers are set to strike over six days during the summer peak – July 26-27, August 5-6 and August 23-24.

Unite regional coordinating officer Wayne King said: “Unite will be engaging positively and constructively in Acas talks.

“Strike action is always a last resort for our members.

“We hope that through these talks we can secure a pay deal which better reflects the important contribution our members make to the smooth and safe running of the UK’s busiest airport.”