A teenager arrested by detectives as part of the investigation into hacking groups Anonymous and LulzSec is due to be questioned by detectives.
The alleged hacker, 18, who is said to use the online nickname "Topiary" and presents himself as a spokesman for the groups, was detained at an address in the Shetland Islands on Wednesday, Scotland Yard said.
He is due to arrive at a central London police station for questioning.
The property where he was arrested was searched by officers from the Metropolitan Police Service's police central e-crime unit following Wednesday's swoop.
Police also searched a house in Lincolnshire and interviewed a 17-year-old boy under caution in connection with the inquiry.
He was not arrested.
The 18-year-old suspect is being held as part of an ongoing investigation into hacking and distributed denial of service attacks, where websites are flooded with traffic to make them crash, against international companies and intelligence agencies believed to be carried out by Anonymous and LulzSec.
Scotland Yard said in a statement: "The man arrested is believed to be linked to an ongoing international investigation into the criminal activity of the so-called 'hacktivist' groups Anonymous and LulzSec, and uses the online nickname 'Topiary' which is presented as the spokesperson for the groups."