The government will push for Gary McKinnon to serve any prison sentence in Britain, Harriet Harman has said.
The deputy prime minister said the government will push for the hacker, who has Asperger's syndrome, to serve his sentence in a British prison if the US authorities find him guilty.
Gary McKinnon lost his appeal to be tried in the UK for hacking crimes last week. He has admitted hacking into US defence department systems and Nasa, and is likely to stand trial in the US despite campaigning to stay in the UK.
US authorities allege he hacked into 97 military computers, deleting vital operating systems and copying encrypted information into his own computer. The US army's computer network in Washington was shut down for 24 hours as a result.
Home Secretary Alan Johnson has said he cannot intervene to prevent McKinnon's extradition to America, saying it would be unlawful for him to do so.