
A group representing more than 90 airlines has threatened to take legal action against Heathrow Airport if it doesn't reach an "amicable" settlement over the costs caused by Friday's 18-hour closure.
Chief executive of Heathrow Airline Operators' Committee Nigel Wicking told Sky News that Heathrow's communication was "appalling".
He said airlines had to wait until midnight on Friday to get confirmation that terminal two would open the next day. It was "not justifiable given the amount of money that has been spent on Heathrow over the years and the fact that it is the most expensive airport in the world".
According to reports, the closure would have cost airlines tens of millions of pounds and stranded thousands of passengers.
Questions have been mounting over how such a critical part of Britain's infrastructure could fail and whether all Heathrow's four terminals needed to shut.
The boss of National Grid told the Financial Times that the electricity transmission network remained capable of providing power to the airport throughout the crisis.
John Pettigrew said there were two other substations able to provide power to Heathrow, showing that the grid was resilient. "Two substations were always available for the distribution network companies and Heathrow to take power," he told the FT.
Heathrow, however, has defended its decision to shut down operations after fire at a nearby substation late on Thursday interrupted its operations.
"Hundreds of critical systems across the airport were required to be safely powered down and then safely and systematically rebooted," a Heathrow spokesperson said. "Given Heathrow's size and operational complexity, safely restarting operations after a disruption of this magnitude was a significant challenge."
While airlines such as British Airways, the worse affected, add up the bill for the closure, the government and Heathrow have both commissioned reviews into what happened.
"It's really important that we do learn the lessons from this, and that's why I think those two reviews...are going to be really critical," Transport Minister Heidi Alexander told Sky News on Monday.
Asked on LBC Radio about whether she had confidence in Heathrow's CEO Thomas Woldbye, Alexander said she wanted to see the results of the reviews. Heathrow is a private company owned by French investment group Ardian, Qatar Investment Authority and Saudi Arabia's Public Investment Fund plus others.