A 17-year-old boy has admitted seven hacking offences linked to the TalkTalk data breach in October 2015.
The teenager, who cannot be named for legal reasons, was arrested in Norwich on November 3 last year and charged with breaching the Computer Misuse Act 1990 following an investigation by the Metropolitan Police's Cyber Crime Unit.
He admitted the seven charges when he appeared at Norwich Youth Court on Tuesday. Sentencing was adjourned to December 13.
Telecoms giant TalkTalk fell victim to what it described as a ''significant and sustained'' attack on its website on October 21, 2015.
The attack resulted in the personal data of nearly 160,000 people being accessed and was branded a ''car crash'' earlier this year by then information commissioner Christopher Graham.
The Information Commissioner's Office fined the firm a record £400,000 last month for security failings that it said had allowed customers' data to be accessed "with ease". The ICO said that in 15,656 cases, bank account details and sort codes had been accessed.
In July, the firm said the fallout from the cyber attack had cost it £42 million.