Heathrowpassengers are being delayed for several hours due to a problem with self-service passport gates.
Some travellers at Terminal 5 posted images of long queues on social media on Wednesday morning, while others were being held on planes due to the congestion.
One wrote on Twitter: “Expected time of waiting for arriving passengers: 2-4 hours.”
It comes less than a fortnight after e-gates failed at airports across the UK.
E-gates – managed by Border Force – allow travellers with biometric passports to pass through border control without a manual inspection.
Heathrow wrote on Twitter: “We’re aware of an issue impacting the e-gates, which are staffed and operated by Border Force.
“We apologise for the impact this is having on your journey.
“Our teams are working closely with Border Force to resolve this as quickly as possible.”
