Dear Theresa and David,

As you are aware, my son Gary McKinnon, who has Asperger's syndrome, a form of autism, was arrested in London in March 2002 for computer misuse and has now been under virtual house arrest for over 10 years while fighting extradition to the US.

People find it hard to believe that this can be happening in Britain in the year 2012, but it is.

Gary was arrested more than 10 years ago for allegedly hacking into Nasa and Pentagon computers from his bedroom in London while searching for evidence of UFOs and free energy that Gary believed was being suppressed by the US government. It's true that Gary left cheeky cyber notes telling the US that their security was virtually nonexistent and that he'd continue disrupting by leaving cybernotes until someone at the top listened to him and installed passwords and firewalls that should have been there in the first place to protect their systems, but weren't.

To his detriment Gary also left a cyber note saying that American foreign policy was akin to state-sponsored terrorism. Had this been scrawled on a wall few would have noticed and to a young man with Asperger's syndrome, telling the truth as he saw it was as natural as getting out of bed in the morning. However Gary had now not only embarrassed the US by highlighting their lack of any basic security, but he had angered them.

No one, but especially someone with Asperger's, could ever have realised the horrendous consequences that would arise from a country whose first amendment is one protecting free speech. Or that an extradition treaty with America, yet to be written, could allow him (without any evidence being presented to a British court) to be forcibly removed from his home, his family and all that he has ever known, to be taken to a foreign land where he could be incarcerated in a foreign prison for up to 60 years. All for a crime that according to the Hi-Tech Crime Unit in 2002, would have attracted a sentence of six months community service in Britain.

My son has now been under arrest for longer than any British citizen ever has. He hasn't raped anyone, he hasn't murdered anyone, so can't understand how this can be happening to him, as no matter how much anyone may choose to exaggerate his crime, the fact is that his crime was tapping on a keyboard in his bedroom in north London in search of information on aliens from outer space.

Gary rarely ever leaves his home as he is traumatised to the core. A boy who cycled, swam, composed music and sang, now sits in the dark with his cats and never wants to see or speak to anyone.

He has no life, and is broken, like a wounded animal with no outlet and no hope, seeing only the dark side and the cruelty that exists in the world.

My only child has lost 10 years of his youth and has aged and died before my eyes.

Ten years of being in a constant state of fear while fighting to stop my son Gary being taken from his home and family has made the days, months and years indistinguishable from each other, as hopes raised to the heavens come crashing down to Earth on a regular basis.

We were elated when in a bid to have Gary tried in the UK, you, our prime minister, raised Gary's case with President Obama during your first televised joint press conference in America in 2010. When President Obama said an appropriate solution would be found, we were moved to tears. We waited and waited and waited, but the months passed and nothing happened.

We were again ecstatic when you raised Gary's case with President Obama for a second time during your second joint press conference in London in 2011, but in spite of President Obama stating that it was a British decision that America would respect and despite great expectations from all who heard it, and constantly being congratulated by strangers in the street, nothing happened.

When Gary's MP David Burrowes asked the American ambassador why the US was still pursuing Gary, his response was: "He mocked us".

I wrote to the Queen during her diamond jubilee to ask her to bestow the gift of mercy on my son who was arrested before even her golden jubilee 10 years previously, but in a response from Buckingham Palace, it seems only our government is privy to the Queen's powers which she herself is unable to use.

I constantly write letters in the hope that the pen really is mightier than the sword and that I can reach souls of courage and compassion in the heart of our government, who can put an end to this decade of mental torture.

Whether the rain falls or the sun shines means little anymore, as we live in this unreal world where Gary sits in the dark and I spend each day and night until the early hours of the morning working on trying to save my son from virtual death. I no longer have any other conversation as I'm unable to escape from this mental imprisonment, grounded in fear.

I am hoping with all my heart that Theresa May our home secretary, who I believe is a strong woman, will have in her heart the courage and compassion that will allow her to do what is right and to give my son his life back.I pray that one day I will see the light return to my son's eyes and that this seemingly never-ending torture will soon come to an end.

If our government is afraid to make a right and just decision for fear of upsetting our friends, then something is wrong with that friendship which must be put right, or we as a nation are allowing our people to be enslaved, making us unable to command respect that by its very nature has to be earned.

We are now at the final hurdle and it takes strength and courage to make that final jump, but jump it we must, if we are to emerge with dignity and self respect.

Our government's first duty is to protect British citizens, including our most vulnerable. Please have the strength to do what is right and to give my son his life back.

With deepest respect,

Janis Sharp

• This article was amended on 7 September 2012. It originally stated that the Crown Prosecution Service had said in 2002 that a crime like Gary McKinnon's would have attracted a sentence of six months community service in Britain. It was actually the Hi-Tech Crime Unit that made that assessment. This has now been corrected