Up to 44 MILLION Britons may have had their data stolen in massive cyber attack on US credit rating firm Equifax Millions of Britons may have been caught up in a cyber attack against an international credit rating company.

Equifax, which is used by BT, Capital One and British Gas among others, was hacked this summer, the company revealed yesterday.

Cyber criminals stole around 209,000 credit card numbers and the personal information of around 182,000 US citizens. But the company also confirmed the hackers had stolen 'limited personal information' from British and Canadian citizens. 

The credit rating company is believed to hold data on around 44million Britons.

James Dipple-Johnstone, of the Information Commissioner's Office, said: 'We are already in direct contact with Equifax to establish the facts including how many people in the UK have been affected and what kind of personal data may have been compromised. 'We will be advising Equifax to alert affected UK customers at the earliest opportunity. 

'In cyber attack cases that cross borders the ICO is committed to working with relevant overseas authorities on behalf of UK citizens.'

A BT spokesman told MailOnline: 'We are aware of the developing story and are monitoring the situation closely.

'Like many companies in the UK, BT uses Equifax services. We are working on establishing whether this breach has any impact on those services.