Telecoms giant TalkTalk has been fined a record £400,000 after its security was bypassed in a major cyber attack.

The Information Commissioner's Office said that the October 2015 attack could have been prevented.

The personal data of 156,959 customers was accessed by hackers, with bank details exposed in 15,656 of the cases.

"TalkTalk’s failure to implement the most basic cyber security measures allowed hackers to penetrate TalkTalk’s systems with ease,” said information commissioner Elizabeth Denham.

"Yes, hacking is wrong, but that is not an excuse for companies to abdicate their security obligations.

“TalkTalk should and could have done more to safeguard its customer information. It did not and we have taken action.

"This record fine acts as a warning to others that cyber security is not an IT issue, it is a boardroom issue.

"They must do this not only because they have a duty under law, but because they have a duty to their customers."