Lawmakers were informed on Wednesday that Heathrow Airport had received warnings about its power supply in the days leading up to the airport's complete shutdown due to an outage that caused widespread disruption. Nigel Wicking, the chief executive of the Heathrow Airline Operators Committee, which represents airlines operating at the airport, stated that he had reported his concerns on two separate occasions.

According to Wicking, his concerns stemmed from "a couple of incidents of, unfortunately, theft of wire and cable around some of the power supply that, on one of those occasions, took out the lights on the runway for a period of time." He conveyed these concerns to a parliamentary committee on transport, stating that the incidents made him question the overall resilience of the airport.

Wicking reported that he had spoken to the Team Heathrow director on March 15 and the chief operating office and chief customer officer on March 19. Subsequently, on March 20, a fire at an electricity substation in Hayes, west London, resulted in the airport's complete closure for the majority of the following day, impacting thousands of passengers globally.

The closure of Europe's busiest airport due to a single fire at a substation has raised questions about its resilience. In response, the government has initiated a six-week investigation into the shutdown. Following the closure, the head of the UK's national grid questioned the necessity of closing the airport, asserting that there had been "enough power" to maintain operations. National Grid chief executive John Pettigrew stated that while losing a substation was an unusual event, two others were available.

However, Heathrow chiefs have maintained that the closure was necessary due to the time required to switch to the alternative substations and conduct safety checks.