A British judge has approved a request by the US for the extradition of an unemployed systems administrator accused of causing US$700,000 in damage by hacking into US military and government computers.

Gary McKinnon is accused of deleting data and illegally accessing information on US government computers between February 2001 and March 2002. Prosecutors allege McKinnon significantly disrupted government computers, causing damage that jeopardised military networks.

British investigators seized McKinnon's computers in March 2002. McKinnon admitted installing remote access software on computers he targeted in the US.

The US filed an extradition request after British officials decided not to prosecute McKinnon because the alleged crimes occurred within the US.

McKinnon's attorneys fought extradition, fearing that he could be classed as an enemy combatant and be held indefinitely, awaiting trial by a military court.

The US said McKinnon would not be held as an enemy combatant, and would face trial in the US District Court for the Eastern District of Virginia.

Judge Nicholas Evans rejected arguments that McKinnon could be subjected to torture and inhuman treatment in the US Evans referred the case to Home Secretary, John Reid to decide whether McKinnon will be extradited.

The soft-spoken McKinnon maintains he didn't damage the computers, owned by the US Army and Navy, the Department of Defense and the NASA space agency. McKinnon, who used the name "Solo" during his exploits, has said he was researching UFOs.

McKinnon used a program called RemotelyAnywhere to control other computers, accessing administrator accounts and gaining passwords for 39 of the 97 computers he is accused of hacking, British court documents said.

US officials claim that McKinnon's actions went beyond mere snooping. They allege McKinnon deleted files from computers at the US Naval Weapons Station Earle in New Jersey, causing the shutdown of 300 computers at a "critical" time after the 9/11 terrorist attacks.

British investigators said McKinnon admitted to leaving a note on a US Army computer that read "U.S. foreign policy is akin to government-sponsored terrorism these days.... I am Solo. I will continue to disrupt at the highest levels."