Lauri Love, 33, faces charges in the United States for allegedly hacking into the networks of the US Federal Reserve, US Army and NASA, among others, in 2012 and 2013.
“The reason I’ve gone through this ordeal is not just to save myself from being kidnapped and locked up for 99 years in a country I’ve never visited, said Love, who has dual British and Finnish citizenship.
Love suffers from Asperger’s syndrome and has also been diagnosed with depression. He was arrested at his home in Britain in October 2013.
“But it’s to set a precedent whereby this will not happen to other people in the future,” Love told reporters outside High Court in London.
“If there is suspected criminality then it will be tried here in the UK and America will not try to exercise exorbitant extra-territorial jurisdiction.”
Kaim Todner, the law firm representing Love, hailed what it called a “landmark judgement”.
“The British justice system has taken the stance that we should deal with the matter ourselves, rather than accept the US government’s demands,” it said.
“It has also been recognised that mental health provisions in US prisons are not adequate to satisfy us that Lauri would not have come to serious harm if he were extradited,” the firm said in a statement.
Judge Ian Burnett handed down the ruling, to cheers from people in the court’s public gallery.
The defence said the United States now has 14 days in which to appeal the ruling at the UK Supreme Court.
Love had appealed against a 2016 British court ruling that he could be extradited to the United States to face the charges.