‘UFO hacker’ Gary McKinnon’s mother Janis Sharp has called on senior Lib Dems, including Deputy Prime Minister Nick Clegg, to honour pre-election pledges to stop his extradition.

Mr McKinnon, 45, who suffers from Asperger’s syndrome, is wanted in the US for allegedly hacking into the Pentagon and NASA’s computers in search of evidence of UFOs 10 years ago.

Mrs Sharp, from Brookmans Park, told the WHT: “I’ve written to him [Nick Clegg] at his constituency and at Parliament to ask for a meeting with him.

“It was a week ago now so he’s obviously got these letters.”

She added: “I’m hoping he’ll respond because he stood with me as well as Chris Huhne, Danny Alexander and Alistair Carmichael.

“They all said if they got into power Gary wouldn’t be going anywhere.”

She added: “Nick Clegg said ‘if he goes to America he would never come back’.”

Mrs Sharp said she was worried that her son would take his own life if he was made to stand trial in the United States.

“We’ve got four of the top people who say Gary would commit suicide if he was extradited”, she said.

Home Secretary Theresa May halted the extradition last year subject to a reassessment of Mr McKinnon’s mental state.

But Mrs Sharp says she continues to struggle to ensure that an independent expert on Asperger’s will carry out the assessment and write the report on Mr McKinnon’s case.

She said that unless the assessment was done by someone well-versed in the condition vital findings could be missed. She added: “Outwardly they [Asperger’s sufferers] don’t show much facial expression so you don’t know what they’re feeling.

“Outside they can look fine, but inside the fires are burning.”

A spokesman for Mr Clegg said: “I can confirm the Deputy Prime Minister has received the letter and will respond in due course.”