UK MPs have been grilling company representatives involved in the response to a Heathrow Airport power outage that saw flight operations grind to a standstill.

Heathrow Airport was warned about the "resilience" of its power supply in the days before a fire which shut down the airport for more than a day last month.

The official said he had raised concerns about Heathrow’s electricity supply days before a power outage forced it to shut down. Heathrow disputed the relevance of the official’s comments.