Police in London arrested an unemployed computer systems administrator on Tuesday, over two years after U.S. authorities said they would request his extradition to answer charges of hacking U.S. government computer systems.

Gary McKinnon, 39, was arrested at his home in northeast London at 6.30 p.m. local time on Tuesday and taken to a central London police station. He will appear in court later Wednesday at an extradition hearing, according to a spokeswoman for the Metropolitan Police Service, London's police force.

Although McKinnon was indicted in the U.S. in November 2002, London police only received the extradition warrant recently, the spokeswoman said.

The extradition warrant alleges that he gained illegal access and made unauthorized modifications to 53 computers belonging to NASA, the U.S. Army, the U.S. Navy, the U.S. Department of Defense and the U.S. Air Force between Feb. 1, 2001 and March 19, 2002, she said.

McKinnon was indicted by the U.S. District Court for the Eastern District of Virginia in November 2002 on seven counts of fraud and related activity in connection with computers.

The indictment alleges he obtained administrator privileges on a number of government computers, and then used this power to delete user accounts and install software enabling him to remotely control the computers.