Heathrow Airport officials defended their response to a fire that disrupted operations for nearly a day, leading to over 1,300 flight cancellations and affecting 200,000 passengers. The fire knocked out one of three electrical substations, raising concerns about the resilience of Britain's energy system. An investigation is underway, with police finding no evidence of foul play. The airport resumed operations after 18 hours, but management decisions during the crisis are under scrutiny.