Delays of up to five hours were reported at Heathrow yesterday after a fire alarm forced the evacuation of the airport’s control tower.
More than 30 flights had to be diverted to Gatwick or Stansted.
Heathrow said that the incident lasted for less than half an hour from 4.30pm but it is believed to have caused knock-on delays for hours.
One passenger told of delays of up to five hours. No aircraft could land or take off, forcing those that had been due to depart to return to the gate.
Heathrow said it “experienced a fire alarm activation that impacted the operation of the airfield for a short while.
“Emergency services responded using our regular safety procedures, and our operations have resumed.”
The disruption was compounded last night when an online check-in system crashed at the London hub.
Travellers complained of cancellations and delays at Heathrow as “system issues” reportedly left British Airways struggling to provide boarding passes to some customers.
BA: “As with a number of airlines we are experiencing some disruption at Heathrow as a result of an issue with a supplier IT system.
“We are working with our supplier to resolve the matter and are sorry for the disruption to our customers’ travel plans.”
BA suffered a substantial computer system failure in May last year caused by a power supply issue near Heathrow which stranded 75,000 customers over a bank holiday weekend.