A teenager suspected of masterminding the notorious international hacking group Lulzsec has been arrested.
Ryan Cleary, 19, was named locally as being arrested in a "pre-planned intelligence-led operation" in Wickford, Essex.
Police have not identified him.
Cleary is believed to have been a "major player" with Lulzsec, a hacking group which has claimed responsibility for a number of online security breaches at organisations including the UK's Serious Organised Crime Agency, the US Senate and the CIA, as well as the games firms Nintendo and Sony.
The teenager was arrested by officers from the force's e-crime unit and is being questioned under the Computer Misuse Act and Fraud Act.
Scotland Yard did not confirm the raid was linked to Lulzsec.
"The arrest follows an investigation into network intrusions and distributed denial of service attacks against a number of international business and intelligence agencies by what is believed to be the same hacking group," said a Scotland Yard spokesman.
"Searches at a residential address in Wickford, Essex, following the arrest last night have led to the examination of a significant amount of material. These forensic examinations remain ongoing."
The Met and Essex Police are working "in cooperation" with the FBI, the spokesman said and the teenager remains in custody at a central London police station.
LulzSec is said to have established itself as a formidable splinter group to Anonymous, the hacking group embroiled in the WikiLeaks fallout.
The group was believed to have initially targeted only US broadcasters, including PBS and Fox, and gaming firms but the Twitter page @LulzSec recently declared its intention to break into government websites and leak confidential documents.
LulzSec is also suspected of hacking into CIA, Sony and NHS websites.
News reports have claimed that LulzSec may have succeeded in hacking into the database of the 2011 Census, which holds details of every UK citizen who filled out the survey earlier this year.
The Office for National Statistics has released a statement saying: "We are aware of the suggestion that Census data has been accessed. We are working with our security advisers and contractors to establish whether there is any substance to this.
"The 2011 Census placed the highest priority on maintaining the security of personal data. At this stage we have no evidence to suggest that such a compromise has taken place."