British Airways is restarting its full flight schedule — but shares are crashing and IT glitch could cost it £100 million

LONDON — British Airways' flights are set to return to their normal schedule on Tuesday, following an IT glitch over the long weekend that saw thousands of people stranded around the world.

BA said in a statement on its website late on Monday evening: "Our IT systems are now back up and running and we will be operating a full flight schedule at Heathrow and Gatwick on Tuesday 30 May."

BA was hit by an IT problem over the bank holiday weekend, which meant 75,000 people around the world faced disruption to their flights. Thousands were left stranded in airports around the world.

Shares in BA's parent company, International Consolidated Airlines Group (IAG), fell 2.7% in Madrid on Monday and crashed over 4% at the open in London on Tuesday. After five minutes of trading on the London Stock Exchange, IAG shares are down over 3%:

Kathleen Brooks, research director at City Index, says: "Even if you give BA the benefit of the doubt it still looks bad — if their systems are not strong enough to withstand a power surge, then this sort of thing could happen again, which could add downward pressure to the IAG stock price."

Explaining the disaster over the weekend, CEO Alex Cruz told the BBC: "There was a power surge and there was a back-up system, which did not work at that particular point in time."

Cruz has faced calls to resign over the IT glitch, which has been blamed on cost cutting that led to IT services being outsourced to India last year. However, Cruz told the BBC: "I don’t think it would make much of use [sic] for me to resign."

James Walker, chief executive of free flights compensation claim site Resolver, told the Guardian over the weekend that the compensation bill to affected customers will likely be more than £100 million. Customers are entitled to compensation under EU law if their flights are delayed by at least 3 hours for reasons within an airline's control.

Walker told the Guardian: "The computer system breaking down is within its control. BA is going to have to pay out and it looks like its costs will be north of £100 million."

BA said in its statement late on Monday evening: "We are extremely sorry for the frustration and inconvenience customers experienced over the Bank Holiday weekend and thank them for their patience and understanding.

"We are continuing to work to get delayed bags to customers as quickly as possible."