Airlines warned Heathrow about risks to its power supply days before the airport was shut down by a substation fire, a Commons committee was told.

The Heathrow chief executive, Thomas Woldbye, apologised for the disruption, which affected more than 200,000 passengers on Friday 21 March, but defended the decision to close as he said staying open was potentially “disastrous”.

Speaking to MPs on the Commons transport select committee, Woldbye said that such a power outage had been seen as a “very low probability event” and the airport had paid for a “supposedly resilient” supply.

However, Nigel Wicking, the chief executive of Heathrow Airline Operators’ Committee, representing airlines, said that incidents including cable theft had made him concerned and he had spoken to senior airport officials.

He told MPs that he had spoken to the Team Heathrow director a week before, and Heathrow’s chief operating officer and chief customer officer on 19 March, only two days before the fire at the North Hyde substation closed the airport. He said the conversations came after “a couple of incidents of, unfortunately, theft of wire and cable around some of the power supply” – which had on one occasion affected the lines on a runway.

Wicking criticised Heathrow for the speed of making a decision to turn to its alternative power supplies and the length of time the process took – claiming that Terminal 5 could have been partly operating much earlier.

However, Woldbye said: “It became quite clear we could not operate the airport safely quite early in this process, and that is why we closed the airport.

“If we had not done that, we would have had thousands of passengers stranded at the airport at high risk to personal injury … The risk of having literally tens of thousands of people stranded at the airport, where we have would have nowhere to put them, we could not process them, would have been a disastrous scenario.”

He added: “Just because the lights were on doesn’t mean all the systems were working … We didn’t have CCTV or fire surveillance.”

Asked if more flights could have entered Heathrow without full power at the airport, he replied: “We would be able to land aircraft … But we would then be leaving passengers on the runway, which would not be acceptable.”

However, Wicking said that the decision to close the airport for 24 hours “should have been constantly under review”, and said more inbound flights could have been processed with manual systems, including immigration controls: “We had checks in with Border Force during the day and they had resource and capability.”