According to the BBC, hackers have managed to get hold of O2 customers’ data by using usernames and passwords first stolen from gaming website XSplit three years ago to log onto O2 accounts.

When the login details matched, the hackers could access O2 customer data in a process known as "credential stuffing". The data included information like phone numbers, emails, passwords and dates of birth.

It is also believed that the same technique has been used to log onto other companies’ accounts.

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