A 19-year old Essex man has been arrested in what is believed to be the first raid on the membership of LulzSec.
"Officers from the Metropolitan Police Central e-Crime Unit (PCeU) have arrested a 19-year-old man in a pre-planned intelligence-led operation," a statement from the MET reads.
"The arrest follows an investigation into network intrusions and Distributed Denial of Service (DDoS) attacks against a number of international business and intelligence agencies by what is believed to be the same hacking group.
"The teenager was arrested on suspicion of Computer Misuse Act, and Fraud Act offences and was taken to a central London police station, where he currently remains in custody for questioning.
"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 PCeU was assisted by officers from Essex Police and have been working in co-operation with the FBI."
There has been no official confirmation that the case is related to LulzSec, though the description leaves little room for doubt.
The move follows rumours that LulzSec had broken into the government's UK Census 2011 database.
The Census press office said it had no evidence that it had been breached. In a statement, it commented:
"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 places the highest priority on maintaining the security of personal data. At this stage we have no evidence to suggest that any such compromise has occurred."