A 41-year-old man has been arrested in connection with attacks on the websites of Theresa May and the Home Office, which were believed to have been carried out by members of the "hacktivist" group Anonymous.
The Stoke man is accused of trying to block access to the sites by flooding them with traffic. Police took computers, telephones and electronic storage devices from a house.
The man, who has not been named, was arrested on suspicion of assisting or encouraging crime contrary to the Serious Crime Act 2007. He was bailed until mid-December.
Detective Inspector Jason Tunn, from the Metropolitan Police's Crime Unit (PCeU), said: "The activity this morning demonstrates the commitment of the PCeU and our colleagues to combat cyber criminality anywhere within the UK and take action against those responsible. Assisting and encouraging cyber crime is a serious matter."