As a result of the decision to deny the extradition request, Shawn Sullivan will not stand trial, and will be allowed to live freely in London.
Sullivan, originally of Fort Benning, Ga., fled the United States after charges were filed against him for allegedly raping a 14-year-old girl and molesting two 11-year-olds in Minnesota between 1993 and 1994.
The Daily Telegraph reported Sullivan was given a suspended sentence in Ireland in 1997 for sexually assaulting two 12-year-old girls.
He was arrested in June 2010 when he tried to enter London using an Irish passport that bore the Gaelic spelling of his name. While he was held on remand, he was married to Ministry of Justice official Sarah Smith. He was since released with an electronic tracking device.
High Court judges said the reasoning behind the decision was that American law enforcement wanted to place Sullivan under "civil commitment" after he served his jail sentence, a treatment program for convicted sex offenders.
No convicted sex offender has been released from the program in Minnesota since its implementation in 1988.
"It is clear to me that were an order of civil commitment to be made, it would be a flagrant denial of this appellant's rights under Art 5.1," Lord Justice Moses said in his ruling.