At least 500 million Yahoo users have had their personal information stolen by hackers, the technology company has confirmed.

Yahoo said account information was stolen from the network in late 2014 during a security breach which the company believes was carried out by a "state-sponsored actor".

In a statement the firm said personal information was taken including "names, email addresses, telephone numbers and dates of birth".

It was reported in May this year that Yahoo, along with Gmail and Hotmail, had been hacked by a young Russian with the information being traded in the criminal underworld.

Yahoo was sold to US telecoms giant Verizon for £3.7bn ($4.8bn) in July.