British officials said they cannot halt McKinnon's extradition any further, despite years of stalling and legal posturing by the U.S. government, British government, and McKinnon's attorneys.  Some human rights experts have stepped up to say the accused hacker suffers from Asperger's Syndrome, a unique form of autism, and extraditing him to face charges in the United States is cruel and inhumane.

"Due to the legitimate concerns over Mr. McKinnon's health, we have sought and received assurances from the United States authorities that his needs will be met," said British Home Secretary Alan Johnson.

Last month, the British High Court said McKinnon should be extradited to face charges, but the U.S. government must ensure he will be properly taken care of.

McKinnon, who admitted to hacking into the computer networks, stated he was looking for evidence the U.S. government covered up the existence of alien life.  His intrusion into networks used by NASA, U.S. Air Force, Army and Navy, and Department of Defense is still considered the "biggest military hack of all time."

If found guilty, the U.S. government has announced he will not be held in a "supermax" high-security facility that houses some of the most notorious criminals convicted in the United States, with a fear he may be sent to Guantanamo Bay.