pPassengers at London’s Heathrow Airport were stranded on planes and in the terminal after a major IT failurea caused British Airways to cancel all flights from Heathrow and Gatwick before 6pm on May 27.ppPassengers who had not yet boarded their flights were advised to leave Heathrow Airport, after being told there was no facility for rebooking “at this time.”ppVideo from the airport shows a large line of people waiting to leave the airport, after BA cancelled all flights. One passenger reporteda that there would be delays in retrieving luggage.