Consumer association Which? has reported British Airways to the Civil Aviation Authority for potentially breaking the law.

Which? says it has gathered evidence that suggests the airline failed to inform passengers of their rights regarding re-routing and compensation when forced to cancel flights due to staff shortages and its recent IT meltdown.

Under EU law, airlines are obliged to re-book passengers on alternative flights at the next available opportunity, even if this means buying seats on rival airlines.

BA told Which?: ‘Where a customer’s flight is cancelled, we always offer options including a full refund, rerouting or re-booking onto another service, including with other airlines. We always meet our legal obligations.”

However, Which? says it has seen some evidence that BA told passengers it would only re-book them on its own flights or with airlines with which it had commercial ties, even if that meant leaving them stranded for days.

Also, Which? says cancellation emails and letters BA issued to passengers made no mention of their rights to compensation, which the consumer association believes may be in contravention of EU261.

In a letter to CAA CEO Richard Moriarty, Which? Director of Policy and Advocacy, Which? Chief Economist Rocio Concha urged him to investigate potential breaches of the law by BA.

He added: “The CAA has written letters to airlines in the past, laying out its concerns around airlines’ failures to comply with their re-routing obligations under EC261, yet, we are still seeing evidence of failures to comply.”

Which? said it also plans to share its evidence against BA with the Competition and Markets Authority.