British Airways' 2017 IT failure: the bank holiday meltdown that cost about £80 million

Over the UK's spring bank holiday weekend of 27-28 May 2017, British Airways cancelled every flight out of its two London hubs after a data-centre power failure took down check-in, baggage and contact-centre systems. The British Airways IT failure statistics that followed are a case study in how a single mechanical fault can cascade into one of the costliest outages in airline history.

What actually went wrong

The fault traced back to a data centre near Heathrow operated for British Airways by contractor CBRE Global Workplace Solutions. An engineer disconnected the site's uninterruptible power supply, then reconnected it in an uncontrolled way rather than following the planned restart sequence. The uncoordinated return of power produced a surge that physically damaged the servers running check-in, baggage handling and customer-contact systems. British Airways said it did have a backup system in place, but it failed to take over as intended, turning what should have been a contained fault into a systems-wide shutdown.

British Airways initially said the engineer had been authorised to be on site but not to carry out the specific action that triggered the surge. CBRE disputed reports that laid the blame directly on its contractor, saying no formal determination of cause had been made at that point.

How big the disruption was

Every British Airways flight scheduled to depart Heathrow and Gatwick on Saturday 27 May was cancelled, with knock-on disruption continuing into Sunday 28 May as aircraft and crews were out of position. Across the weekend, British Airways cancelled roughly 726 flights, and the airline said around 75,000 passengers were affected — delayed, rebooked or stuck without a flight at all, on one of the busiest travel weekends of the UK calendar.

Recovery took longer than the headline "two-day meltdown" suggests. British Airways did not confirm it was running a full schedule from Heathrow and Gatwick again until Tuesday 30 May — three days after the initial power failure — and said more than two-thirds of the affected passengers had reached their final destination by the end of the bank holiday Monday. Rebuilding the IT estate and repositioning aircraft and crew around the world took considerably longer than fixing the original electrical fault.

A backup system that exists on paper is not the same as a backup system that switches on when it's needed.

What the meltdown actually cost

IAG chief executive Willie Walsh gave the first public cost estimate less than three weeks later, telling reporters the disruption would cost "in the order of £80 million" — covering lost revenue plus the expense of rebooking, hotels and passenger compensation. He was careful to call it an initial assessment rather than a final number.

Independent analysts arrived at broadly similar figures by different routes. Goodbody's Mark Simpson put the total cost at around €82 million, while Cantor Fitzgerald's Robin Byde estimated a range stretching toward £100 million once every cost line was included. Other contemporaneous estimates of the full bill, reported by CNN Business, clustered around €100 million (roughly $112 million at the time). IAG shares fell about 4.3% when markets reopened the following Tuesday, as investors priced in the damage.

The reckoning

British Airways went on to sue CBRE over the outage, arguing the contractor's staff were responsible for the way power was restored to the data centre. The dispute ran for two years before the two companies reached a confidential settlement in 2019, with no admission of liability from either side and no public disclosure of the sum involved.

The episode also became a reference point in the airline-cost-cutting debate: British Airways had outsourced parts of its IT infrastructure management to CBRE as part of a wider cost-reduction programme, and critics argued the single point of failure at one data centre showed the limits of that approach. The airline has since said it invested further in resilience and redundancy across its technology estate.

Why this outage still matters

Three points make the British Airways IT failure statistics worth revisiting years later. First, the trigger was mundane — a power reconnection error, not a cyberattack or software bug — which is a reminder that physical infrastructure failures remain a real risk for digital-dependent operations. Second, the disruption showed how quickly a single-site fault can become global: passengers as far away as Hong Kong and San Francisco were affected because the failed systems handled worldwide check-in and baggage, not just UK departures. Third, the gap between the incident (a few minutes of uncontrolled power) and the bill (tens of millions of pounds) illustrates how disproportionate downtime costs can be for an airline running a tightly scheduled global network.

The timing made it worse. Late May is the start of the UK's peak half-term and bank-holiday travel window, so the cancelled flights and stranded passengers landed on one of the busiest and most visible weekends of the year for British aviation, amplifying both the reputational damage and the compensation exposure under EU passenger-rights rules that were still in force in the UK at the time.

• Saturday 27 May 2017: all Heathrow and Gatwick departures cancelled.
• ~726 flights cancelled across the weekend of 27-28 May.
• ~75,000 passengers affected.
• ~£80 million initial cost estimate from IAG; independent estimates ranged toward £100 million / €100 million.
• CBRE lawsuit settled confidentially in 2019.

Frequently asked questions