Equifax has admitted that almost double the number of UK customers had their information stolen in a major data breach earlier this year than it originally thought, and that millions more could have had their details compromised.

The credit rating firm said it is contacting nearly 700,000 customers in the UK to alert them that their data had been stolen in the attack, which was revealed in September.

The company originally estimated that the number of people affected in the UK was "fewer than 400,000".

But on Tuesday night it emerged that cyber criminals had targeted 15.2 million records in the UK. It said 693,665 people could have had their data exposed, including email addresses, passwords, driving license numbers, phone numbers. The stolen data included partial credit card details of less than 15,000 customers.

Hackers potentially compromised a further 14.5 million records that could have contained names and dates of births.