MADRID — A technological failure which stranded tens of thousands of British Airways (BA) passengers in May will cost the company around £80 million, Willie Walsh, chief executive of BA parent International Airlines Group (IAG), said on Thursday.

The figure was an initial estimate, Walsh told at the company’s annual shareholders meeting in Madrid.

In addition to BA, IAG owns Aer Lingus, Vueling and Spain’s Iberia.

BA suffered a disruption at London’s Heathrow and Gatwick airports when a power surge knocked out its IT system forcing it to cancel almost two-thirds of all flights on May 27, which fell on a busy bank holiday weekend.

Heathrow suffered further setbacks on Thursday after a baggage system failure prevented luggage from being checked in at terminals 3 and 5. The problem has been resolved.

(Reporting by Robert Hetz; writing by Paul Day; editing by Jason Neely)