Edinburgh-based venture capital investor Luke Heron, right, is calling on other Scottish businesses and the “celebrity bandwagon” to help build up an emergency defence fund for the Glasgow-born computer expert, who faces charges of hacking into 97 US military computers between 2001 and 2002.

“I hope my money never needs to be used, I hope it never comes to that,” Heron, 30, told the Sunday Herald. “But the reality is [McKinnon] now lost another appeal and people need to face up to the fact that it’s looking increasingly likely he’s going to go over there and a US legal case is going to cost in the millions.”

McKinnon’s plight has become something of a cause celebre in recent years, with everyone from Boris Johnson to Terry Waite, Sting and Jane Asher speaking out against moves to force the autistic Scot to stand trial in the US.

On Friday, David Cameron described him as a “vulnerable young man”, whose case raised “serious questions about the workings of the Extradition Act, which should be reviewed”.

Heron said: “I just felt this was something tangible that I could do … It’s very easy to join a list of people saying, ‘This shouldn’t happen’, but they have far more clout and far more money than I can ever dream of having.

“The best thing that can happen for Gary is that the next chapter in the media story needs to be about money. The US keep saying how much damage he is supposed to have caused [$700,000, which is about £418,000].

“If that is their biggest problem, I genuinely would write a cheque for it now, if it would close the matter.” A

one-time university dropout who puts his success down to “getting lucky a couple of times”, Heron was partly inspired to offer financial backing to McKinnon based on his own experiences working with an autistic boy during his eight months as a student in St Andrews.

While undertaking a course in Medieval History at the university, he began volunteering and became involved with a family in Cupar whose son had Asperger’s syndrome – the same condition that McKinnon was diagnosed with last year.

“One of the greatest regrets of my life is, firstly, cutting off my university career, but also feeling that I had completely and utterly let down their child, although they had many other people to help,” said Heron.

“This is not about putting right a wrong, I think Gary’s case is completely unique, but that is my only connection, and an all too brief involvement, with someone with autism.”

McKinnon, 43, lost the latest in a long line of legal battles to prevent his

extradition to the US, when the High Court on Friday rejected calls for a

judicial review. Although his only contact with the McKinnon family so far has been via their lawyer, Heron is aware that

his message of support “has been passed on”.

He hopes that the “ridiculous” situation might be averted if the US authorities take into account the inevitable “media storm” that

McKinnon’s extradition would spark – and is banking on a change of heart under the Obama administration.

“The Extradition Treaty was never [intended] for this purpose,” he said. “I think the US has presented Gary as some terrible criminal who is intent on bringing down the United States military, which is just complete and utter fantasy.”