Airlines warned Heathrow about risks to its power supply days before the airport was shut down by a substation fire, a Commons committee was told. The Heathrow chief executive, Thomas Woldbye, apologised for the disruption, which affected more than 200,000 passengers on Friday 21 March, but defended the decision to close as he said staying open was potentially “disastrous”. Speaking to MPs on the Commons transport select committee, Woldbye said that such a power outage had been seen as a “very low probability event” and the airport had paid for a “supposedly resilient” supply. However, Nigel Wicking, the chief executive