Millions of Britons' data at risk in ISP cyberattack

The personal data of millions of Britons could be at risk after telephone and broadband provider TalkTalk was hit by a "significant and sustained" cyber-attack, the company said Friday.

 TalkTalk said information including customer names, addresses and bank details could have been compromised, and that it had informed London's Metropolitan Police Cyber Crime Unit.

 "There is a risk that all of our customers' personal data has been accessed," chief executive Dido Harding told the BBC.

 In a statement on its website, the company said that "not all of the data was encrypted".

 Harding said the company had also been contacted by someone purporting to be the hacker who was "looking for money".

 She said she was not sure whether it was an individual or a group making the demand.

 Police had no information on those behind the attack, but said they were "aware of speculation regarding alleged perpetrators".

 The company has some four million broadband subscribers, and has offered customers free credit monitoring over the next year to spot unusual bank transactions.

 TalkTalk shares plunged at the start of trading on Friday but recovered in the afternoon and were down 2.05 percent at 263 pence on the London Stock Exchange.