Computer hacker Gary McKinnon is refusing further medical tests by a Home Office-appointed expert as part of his ongoing fight against extradition to the United States.

His mother, Janis Sharp, has said her son will not undergo a final psychiatric examination before the Home Secretary decides whether to order his extradition.

The US authorities want Mr McKinnon, from north London, to face trial for hacking into military computers a decade ago, and American officials are demanding that Mr McKinnon is tried in the States. This is despite experts warning that his mental condition could lead him to commit suicide if taken out of the UK.

On Tuesday the case will return to London's High Court, a move which is, according to a family spokesperson "in anticipation of an imminent Home Office decision".

McKinnon faces up to 60 years in jail if convicted.

The 46-year-old, who suffers from Asperger's syndrome admits to "the biggest military computer hack of all time", but claims he was looking for evidence of UFOs.