The Welsh Secretary said it would be better for Mr McKinnon, who suffers from Asperger’s syndrome, to be “assessed in a British context”.

And he refused three times to back the decision of Home Secretary Alan Johnson that the extradition to America should take place, according to a newspaper.

Glasgow-born Mr McKinnon, 43, is wanted for trial on charges of hacking into US military networks. His supporters say his only crime is being a “UFO eccentric” who searched for evidence of extraterrestrials.

They argue he could be tried in the UK if the government acted to halt his extradition, but Mr Johnson said it would be illegal for him to intervene.

Mr Hain told a newspaper: “I would have preferred it if I had been in the position to have a say on this – and the law is just following its course – to have had the Director of Public Prosecutions (Keir Starmer) made this decision.

“We could then have had a position where it could have been assessed in a British context – after all, he was sitting in his bedroom by a computer, as a kind of computer geek zapping the American defence system and therefore he was committing an offence on British soil.”

Mr McKinnon’s mother, Janis Sharp, told GMTV: “I was so upset when the Home Secretary spoke about 9/11, spoke about the people who died and mentioned Gary’s name. It was almost like he was trying to incriminate him in some way, it’s like some sort of smear campaign against a guy with Asperger’s. It’s ridiculous.

“So for Peter Hain to stand up and talk from the heart was so refreshing.”

She said if he was taken to America with no family support it would cause mental breakdown and he would become suicidal.

“It’s very hard but I just have to keep fighting because it’s wrong, it’s unjust and I’m determined that Gary is going to stay here.

“It’s affected him mentally, emotionally, physically. He has terrible heart pains. He has fears. If someone touches his shoulder he jumps.

“To have that level of stress for such a long time and trying to keep a lid on it I’m just scared he’s going to explode.”

Writing in another newspaper yesterday, Mayor of London Boris Johnson accused the Home Secretary of “passing the buck” by failing to intervene to prevent the extradition to America.

He said the British authorities’ refusal to stop Mr McKinnon’s removal would count as “one of the most protoplasmic acts of self-abasement since Suez”.

The mayor described Mr McKinnon as a “classic British nutjob” who should be protected by government rather than be “catapulted” across the Atlantic.

In a statement, the Home Secretary said Friday’s High Court ruling, in which Mr McKinnon failed in his bid to avoid removal to America, made clear “it would be illegal for me to stop the extradition”.

He said: “Mr McKinnon is accused of serious crimes and the US has a lawful right to seek his extradition, as we do when we wish to prosecute people who break our laws.”