British Airways has cancelled all flights out of London Heathrow and Gatwick due to a massive worldwide failure of their IT systems. The airline has announced that they haven’t found any evidence of a cyber attack.
Heathrow Airport has announced on Twitter that all flights until 1800L (1700Z) have been cancelled due to this failure.
Meanwhile the situation in the terminals at Heathrow is chaotic, with flight gates being announced using manual blackboards and huge queues are forming at check-in boards.
[UPDATE 1540Z] British Airways has announced that flights have been cancelled for the rest of the day due to their IT systems failing catastrophically.