Thousands of global travelers using British Airways (BA) have had flights delayed or cancelled on Wednesday after the firm suffered an IT outage.
On its website the airline said a systems issue was affecting both check-in and flight departures.
In a tweet pinned to on BA's Twitter account on Wednesday, the airline said it was working as "quickly as possible" to resolve the issue.
BA is advising customers to check the status of their flights before making the journey to their airport.
The airline, which is owned by International Airlines Group, said customers booked on short haul flights out of London were being asked to travel on a different day.
British Airways was unable to confirm to CNBC how many people or flights had been affected.
It's the third major IT failure for the airline in two years after 672 flights were cancelled in May 2017 and another outage at Heathrow in July last year.