Airlines and passengers likely to face days of disruption after fire at substation causes travel chaos

• Heathrow airport closed –live updates

Depending on whose fault it eventually turns out to be, this was a power cut in just the wrong – or right – place. As Britain’s biggest airport, Europe’s main gateway to the Americas, and the apple of Rachel Reeves’ eye for growth, Heathrow’s shutdown gave a supersized significance to a substation fire.

Some were quickly out of the blocks to question the creaking state of national infrastructure. Where were the back-up systems – or indeed the further failsafes when the back-ups went up in smoke? Should Heathrow be better prepared, given the critical importance of the hub airport – not least to the 250,000 or so international travellers who were expecting to fly in or out yesterday?