Cruz has faced a backlash from customers and calls to stand down in the wake of the technology failure which affected more than 75,000 passengers across the globe.

Since the systems failure on Saturday (May 27) BA has insisted that the Spaniard will not resign with a spokesperson for Walsh telling the Telegraph: “Alex has Willie’s absolute support. As far as Willie is concerned, this has nothing to do with the decisions Alex has made.”

Walsh, the chief executive of IAG, is yet to speak publically since the IT meltdown.

The comments come as more clues have emerged into the cause of the systems failure which is still being investigated.

The investigation, which according to the Telegraph is being led by Cruz himself with the help of external power supply specialists, is focusing on the uninterruptible power supply (UPS) to Boadicea House, one of two data centres near Heathrow airport.

It is reported that when recovering from the outage, the data centre resumed with an uncontrollable surge of power which should have been gradual.

The carrier is looking at whether the fault was down to human error or a mechanical failure.

According to Telegraph sources, the power surge caused “catastrophic physical damage” to BA’s servers, which contain customer and crew information, operational details and flight paths although no data is believed to have been lost and the servers have been rebuilt.

If the power had have been restored more gradually, “sources close to the airline” say BA could have been able to handle the outage, the newspaper reports.

BA is running a full schedule of flights today (May 31).