BA urged to 'do more' over compensation for bank holiday flight chaos
The airline risks creating "further stress, inconvenience and financial hardship for passengers", according to Which?
British Airways has been urged to automatically compensate passengers affected by the recent disruption and not wait for them to submit claims.
Consumer group Which? said the airline should go beyond the legal requirements or it would be in "grave danger" of failing customers.
Around 75,000 people had flights cancelled or delayed after after a power surge caused an IT system failure on 27 May.
The chaos lasting for three days, with some passengers forced to sleep on terminal floors and complaints that staff did not keep passengers properly informed.
EU law allows those affected up to €600 (£524) in compensation and they can also claim for things such as hotels, meals and phone calls.
Alex Neill, Which? managing director of home product and services, has written a warning letter to BA chief executive Alex Cruz.
She says the "bare minimum" level of compensation would "cause further stress, inconvenience and financial hardship for passengers, and of course further damage to BA's reputation".
She says airline compensation is "out of step with other markets, like energy and water, where compensation is automatically awarded to customers for severe disruption to, or complete absence of, service".
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"Given the scale of the problem BA has experienced, we strongly believe it is only right that you do more than the legal minimum," says Ms Neill.
She says that BA has the chance "to minimise the additional stress and inconvenience you cause your customers and ensure they are not pushed into the arms of claims management companies, who will take a large part of the money they are owed".
The Association of British Insurers has said passengers were being "passed from pillar to post" after BA's website suggested they claim through their insurer first.
A BA spokeswoman said: "We sincerely apologise for the difficulties and frustration customers faced during the huge disruption across the bank holiday weekend.
"We will fully honour our EU compensation obligations and have set up a link on the home page of our website to enable customers to submit their claims as quickly and conveniently as possible.
"We have no desire to be obstructive in any way and have put additional resources into our call centres to process claims as speedily as possible."
- British Airways