More than 100 MPs are calling on President Barack Obama to block the extradition of an autistic British man accused of hacking into US computers.
The 105 cross-party backbenchers who have signed a letter to the American leader, stressing their "deep concern for the safety" of Lauri Love, 31.
They point out that he has "a long history of serious mental health issues, depression and some episodes of psychosis" and are hoping that Mr Obama will call a halt to the extradition before he leaves office next year.
US authorities have been fighting for Mr Love, who lives with his parents near Newmarket in Suffolk, to face trial over charges of cyber-hacking, which his lawyers say could mean a sentence of up to 99 years in prison if he is found guilty.
He is alleged to have stolen huge amounts of data from US agencies including the Federal Reserve, the US Army, the Department of Defence, Nasa and the FBI, in a spate of online attacks in 2012 and 2013.
The case has echoes of that of Gary McKinnon, another alleged cyber-hacker with Asperger's, who eventually had his extradition blocked by then home secretary Theresa May after a decade-long battle.
The MPs point out the UK has prosecuted at least 12 people who have hacked US-based computer systems.
The MPs wrote: "Indeed, Mr Love would be the first UK-based computer hacker to be extradited and denied the opportunity to face a full prosecution in the UK.
"The UK criminal justice system is equipped to bring justice through sentencing and rehabilitating people who are adjudged to have committed these crimes. Many of these 12 cases did not involve individuals who have significant mental health issues, nor Asperger syndrome and were not at a high risk of suicide, yet they were not extradited.
"We would like to ask, why then is the United States insistent on Mr Love's extradition despite the UK having a proven track record of appropriately sentencing and rehabilitating individuals who have committed computer-hacking offences against the US?"
Mr Love, who also suffers from depression and severe eczema, has said a jail term in the US would cause his health to deteriorate and would lead to a mental breakdown or suicide.