A power outage at British Airways that disrupted tens of thousands of people’s travel plans last weekend plunging hubs Heathrow and Gatwick into chaos, was reportedly caused by a staff blunder.

According to The Times, a power supply unit at the centre of the outage was in perfect working order and was deliberately shut down which triggered the disturbance. The paper reported that an investigation of the episode will therefore likely focus on human error.

According to The Times, the incident likely concerned a so-called uninterruptable power supply, or UPS, which is designed to deliver a smooth flow of power from the main with a fall-back to a battery-powered back-up and a diesel generator.

British Airways’ parent company, International Airlines Group, this week explained that the supply of power to a key data centre was lost and an uncontrolled reboot of the system subsequently shut down the entire system.

An investigation has already revealed that the UPS was in full working order at the time, The Times reported. Citing a source, the paper said that it was rumoured a maintenance contractor had accidentally switched the supply off.

Bill Francis, head of IT at IAG, sent an email to staff, seen by the Press Association, which appeared to confirm that the outage was not caused by an IT failure or issues relating to software.

Last weekend, British Airways was forced to cancel around 800 flights from Gatwick and Heathrow as a result of the disruption.

Flight compensation website Flightright.com said that BA would likely have to pay approximately €61m (£53m) in compensation under EU rules, a figure that does not include the cost of reimbursing customers for hotel stays.

Several airlines have been hit by computer glitches over the last year, but analysts said that the duration and scale of BA’s outage was unusual.