Heathrow Airport is considering legal action against National Grid after a report found the fire which caused the airport to shut down was a result of a known fault at an electrical substation. An investigation found that National Grid, which owns the substation which supplies Heathrow, had been aware of a problem since 2018 but failed to fix it.

National Grid (NYSE:NGG) -4.9% in Wednesday's trading after an investigation found the fire which caused London's Heathrow airport to shut down in March, which led to thousands of canceled flights and stranded passengers,

HEATHROW may sue the National Grid after a probe found a fault causing the huge substation fire was identified seven years ago. The blaze in March halted flights for 24 hours — affecting 270,000