A 15-year-old boy has been arrested in Northern Ireland over the TalkTalk cyber attack last week, Scotland Yard has said.
In a statement, Metropolitan Police said a house had been searched in County Antrim on Monday afternoon at about 16:20 GMT.
The boy was arrested on suspicion of offences relating to the Computer Misuse Act 1990.
He has been taken into custody at Antrim police station and is being questioned by detectives from the Police Service of Northern Ireland.
A search of the address is ongoing and inquiries continue.
The statement said this was a joint investigation involving the Police Service of Northern Ireland (PSNI), and detectives from the Metropolitan Police Cyber Crime Unit (MPCCU).
News that the TalkTalk website had been hit by a "significant and sustained cyber-attack" broke last Wednesday.
The phone and broadband provider, which has over four million UK customers, said banking details and personal information could have been accessed.
A criminal investigation was launched on Thursday.
The company said it did not know how much of their customer information had been encrypted.
Business leaders have called for urgent action to tackle cyber crime in the wake of the TalkTalk attack.
On Monday, MPs said an inquiry would be launched into the cyber-attack that could have put customers' details at risk. Culture minister Ed Vaizey told the House of Commons the government was not against compulsory encryption for firms holding customer data.
Shares in the telecoms company fell more than 12% in Monday trading, extending its losses from last week when news of the attack first emerged.
TalkTalk has said the cyber-attack was "smaller" than originally thought.
In a statement, Metropolitan Police said a house had been searched in County Antrim on Monday afternoon at about 16:20 GMT.
The boy was arrested on suspicion of offences relating to the Computer Misuse Act 1990.
He has been taken into custody at Antrim police station and is being questioned by detectives from the Police Service of Northern Ireland.
A search of the address is ongoing and inquiries continue.
The statement said this was a joint investigation involving the Police Service of Northern Ireland (PSNI), and detectives from the Metropolitan Police Cyber Crime Unit (MPCCU).
News that the TalkTalk website had been hit by a "significant and sustained cyber-attack" broke last Wednesday.
The phone and broadband provider, which has over four million UK customers, said banking details and personal information could have been accessed.
A criminal investigation was launched on Thursday.
The company said it did not know how much of their customer information had been encrypted.
Business leaders have called for urgent action to tackle cyber crime in the wake of the TalkTalk attack.
On Monday, MPs said an inquiry would be launched into the cyber-attack that could have put customers' details at risk. Culture minister Ed Vaizey told the House of Commons the government was not against compulsory encryption for firms holding customer data.
Shares in the telecoms company fell more than 12% in Monday trading, extending its losses from last week when news of the attack first emerged.
TalkTalk has said the cyber-attack was "smaller" than originally thought.