The airline said there was no evidence that any personal information had been misused and that it would be contacting all affected customers in the next few days.

It confirmed the email addresses and travel details of approximately nine million customers were accessed as well as credit card details of 2,208 customers.

In a statement, EasyJet said: “There is no evidence that any personal information of any nature has been misused, however…we are communicating with the approximately nine million customers whose travel details were accessed to advise them of protective steps to minimise any risk of potential phishing.

“We are advising customers to continue to be alert as they would normally be, especially should they receive any unsolicited communications. We also advise customers to be cautious of any communications purporting to come from EasyJet or EasyJet Holidays.

“We’re sorry that this has happened, and we would like to reassure customers that we take the safety and security of their information very seriously.”

The airline said all affected customers will be notified no later than 26 May. If you are not contacted then your information has not been accessed, it added.