Gary McKinnon, the North London hacker accused of 'the biggest military hack of all time', heard yesterday that he has won the right to have his final appeal against extradition to the US heard by the House of Lords.

McKinnon, 41, faces a prison sentence of up to 45 years if found guilty of gaining access to 97 US military and Nasa computers between 2001 and 2002.

During a period of 18 months, McKinnon is alleged to have caused £370,000 worth of damage to US government machines. He claims the damage was not intentional and he was simply looking for evidence of UFOs.

McKinnon has never denied that he accessed the computer networks of a wide number of US military institutions but says he considered his hacking a 'game'.

He also says that because offences took place in the UK, he should be tried in this country. A date has not yet been set for the hearing.