British Airways passengers on flights out of the UK have seen departures disrupted after a computer glitch hit check-in procedures.
Passengers have been unable to check-in for flights online, with staff resorting to paper ticketing.
At Heathrow, 81 flights have been cancelled while the carrier has cancelled a further ten Gatwick flights.
More than 200 flights have been delayed across the UK, with the airline advising customers to allow extra time at airports.
In a statement, British Airways said: “We are experiencing some systems problems this morning which are affecting check-in and flight departures.”
The carrier said the issue was not a global outage, but a problem with two separate systems - one which deals with online check in, the other that deals with flight departures.
Problems have also been reported at Stansted Airport.
British Airways said it is working as quickly as possible to resolve the systems issue which “has resulted in some short-haul cancellations and delays from London airports”.
A statement added: “We are offering customers booked on short-haul services departing from Heathrow, Gatwick and London City today, the opportunity to rebook to another day.”
The disruption comes after a tough week for British Airways.
Yesterday, a plane was evacuated after smoke filled the cabin shortly before landing.
Flight BA422, which departed London Heathrow, landed in Valencia.
Passengers had to slide down emergency chutes to the runway, with the carrier forced to apologise to the 175 passengers on board the aircraft, an Airbus A321.
British Airways has also been talking to pilots’ union, Balpa, to reach an agreement on pay in order to avoid strike action.
Following a failure to gain an injunction at the court of appeal, strike dates are expected to be confirmed.
However, Balpa has yet to issue any dates and by law they must give us at least 14 days’ notice of any disruption.