British Airways was warned by IT experts that it was vulnerable to a hack in which criminals could steal customers' card details earlier this year, it has been claimed.

The airline announced on Thursday that it had suffered a major hack compromising the bank card information of around 380,000 customers.

Due to strict new data protection laws British Airways is now facing a fine of up to £897m, or 4 per cent of its parent company's turnover, if regulators find it has not done enough to keep customer data safe.

The Telegraph can reveal that last year the airline failed an industry standard for consumer data protection, which is required by card providers Visa and Mastercard for all companies accepting, transmitting or storing any cardholder data.

The standard, called the Payment Card Industry Data Security Standard, is a set of security standards designed to ensure that companies which accept, process, store and transmit credit card information keep it secure.

British Airways said it had a number of fully operational monitoring tools which it used to check for suspicious activity. It added that the Standard related to the protection of customer accounts, none of which were compromised during the attack.