Gary McKinnon, 40, who said he had hacked into NASA and US military systems to check for material on UFOs, has six weeks to submit evidence to John Reid, the Home Secretary, who will make the final decision.
McKinnon was arrested last June following charges by US prosecutors that he illegally accessed 97 government computers, including Pentagon, US army, navy and NASA systems, causing £375,000 damage. He admitted hacking into the systems, but denied causing any damage.
Appealing to Mr Reid not to extradite him, McKinnon said: “Do right by your subjects.”
McKinnon, who was born in Milton of Campsie, near Glasgow, before moving to London as a boy, fears he will be sent to Guantanamo Bay.
A Home Office spokeswoman said
the government always sought assurances that torture or the death penalty would not be applied before agreeing to extradition.
Prosecutors accused McKinnon of crippling US defence systems in the wake of the 11 September, 2001, attacks.
At the time of the indictment, Paul McNulty, the US attorney for the eastern district of Virginia, said: “Mr McKinnon is charged with the biggest military computer hack of all time.”