A British computer expert accused by Washington of the "biggest military hack of all time" lost an appeal on Tuesday against plans to extradite him to the United States to stand trial. Gary McKinnon was arrested in 2002 following charges by U.S. prosecutors that he illegally accessed 97 government computers -- including Pentagon, U.S. army, navy and NASA systems -- causing $700,000 worth of damage.

Two of Britain's leading judges rejected a High Court challenge by McKinnon to an earlier court order backed by Britain's Home Secretary that he should be extradited.

"We do not find any grounds of appeal against the decision," said one of the judges, Lord Justice Maurice Kay.

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

McKinnon's lawyers had argued that sending him to the United States would breach his human rights and should not be allowed on the basis that his extradition was sought "for the purpose of prosecuting him on account of his nationality or political opinions."

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

If found guilty in the U.S, McKinnon could face up to 70 years in jail and fines of up to $1.75 million.

He is expected to apply to the House of Lords, Britain's highest court, for permission to challenge Tuesday's ruling.