(LONDON) — British Airways canceled all flights from London’s Heathrow and Gatwick airports Saturday as a global IT failure causes severe disruption for travelers. The airline said it was suffering a “major IT systems failure” around the world. It didn’t say what was causing the problem but said there is no evidence of a cyberattack. BA said terminals at Heathrow and Gatwick had become extremely congested and cancelled all flights from those airports until 6 p.m.