A Britishcomputer expert has lost his appeal against extradition to the US to be tried for what Washington calls the "biggest militaryhack of all time."

GaryMcKinnon was arrested in 2002 and charged by US prosecutors ofillegally accessing 97 computers - including Pentagon, USmilitary and NASA systems - causing $700,000 worth of damage.

An appealby McKinnon to an earlier court order, backed by the British government, thathe be extradited was rejected by judges at the High court on Tuesday.

LordJustice Maurice Kay said: "Mr McKinnon's conduct was intentional andcalculated to influence and affect the US government by intimidation andcoercion."

"As a result of his conduct, damage was caused to computers by impairingtheir integrity, availability and operation of programmes, systems, informationand data on the computers, rendering them unreliable," Kay said.

Execution threat

McKinnon'slawyers argued that sending him to the US would be a breach of the41-year-old's human rights.

BenCooper said he would now try to have the case heard in the House of Lords, Britain'shighest court, including an alleged threat from US prosecutors thatMcKinnon "would fry."

McKinnonand his lawyers expressed fears he could be held indefinitely without trial atthe US prison camp in Guantanamo Bay, Cuba.

But the US government said it had given assurances tothe British government that it would not make McKinnon subject to"Military Order Number One", which allows the US president todetain suspects indefinitely.

McKinnon,whose hacking name was "Solo," has admitted gaining access to USgovernment computers but denies causing any damage.

PaulMcNulty, the US Attorney for the eastern district of Virginia, said "MrMcKinnon is charged with the biggest military computer hack of all time."

If foundguilty in the US,McKinnon could face up to 70 years in jail and be fined up to $1.75 million.