Moazzam Begg and his wife Sally had fulfilled a lifelong dream to teach and work in Afghanistan, moving to Kabul with their three children a few months before the events of 9/11.
There they built wells giving access to fresh water in remote villages. When the US invaded Afghanistan they temporarily left for Islamabad. Their house was raided, and Moazzam was beaten up and taken away in the boot of a car by two US and two Pakistani soldiers. He was taken first to Kandahar, then Bagram airbase by the US military before being transferred to Guantanamo Bay. He has never been charged with any crime and has been denied any legal access. When five British citizens were released from the camp last month Moazzam was not among them.
Azmat-U Begg, Moazzam's father, has just returned from an arduous trip which took him, along with Terry Waite, Vanessa Redgrave and a delegation of other detainees' families, to lobby various institutions in the US to publicise his son's case.
He spoke in the Presbyterian Church in Washington where Martin Luther King delivered some of his most famous speeches. People shook his hand and hugged him, and candles were lit for those lost sons that nobody has heard from in such a long time. But despite support from others he remains genuinely perplexed at the lack of justice for his son. Jack Straw went to Washington just after their delegation 'and tried to block everything we were trying to do'.
The family have not heard from Moazzam since 23 October last year - he passes me the letter. It is short, and most of it has been crudely obscured in black marker pen by the US authorities. 'He has been in solitary confinement for ten months and the Tipton boys say he has been moved to Camp Echo, which is higher security, but why?' Moazzam has not been charged, has no legal representation and the 'nice woman' at the Foreign Office says there is nothing she can do. 'You can only guess what is happening. This is a gross violation of human rights - this is not democracy, it is something else,' he insists.
Mr Begg does not preach Moazzam's innocence as there have been no charges laid against him, yet he has been campaigning, despite ill health, unstintingly for his son. 'I try very hard to understand but I can't,' he says. 'He has been kept away from his wife and children for two years. He has been tortured. He told me that for one year he was kept away from all natural light. He couldn't see the sun, the moon - he couldn't see the sky at all. He has been deprived of the most basic treatment. Now he has been transferred to Camp Echo he cannot even walk in his cage. Before he told me he could stand and at least do some exercise alone. Now they have stopped him from doing that.'
He shows me some photographs of Moazzam's four children, including his 18 month old youngest son who he has never seen. 'Look at the children. It is common sense that he would never have put them at risk. At the time of his arrest there were leaflets dropped around Islamabad offering $5,000 for information on Al Qaida. It is a poor country - there are many stories of men being held in Guantanamo Bay who are simple rickshaw pullers and the like. My son should be brought back to this country. He should be tried in the country he was born and brought up in. I have no objection to that. If he is guilty then punish him, but if not let him go - this is not the Dark Ages.'
A retired bank manager, Azmat was born in India. 'I am a proud British citizen. I come from an army background, and my family served the British for generations. But now the government is saying we are traitors.
'I will go wherever I can to fight for justice for my son. I have lived all my life in the west. We're not fundamentalists, but now they are splitting society. They are trying to frighten people. Billions are being spent for security purposes, but to try and justify the amount they have spent and the statements they have made Muslims are being arrested. How can we be terrorists? We live here, we have families here, but now if you have one little beard you will be arrested. But our families will suffer the same as anyone is going to suffer. We are all living here peacefully - there are no signs of terrorism. It is the government's duty to protect us, but bullets and bombs don't have names on them - they affect everybody. It is our government who dropped the bombs on Iraq.'
The Birmingham suburb of Sparkhill is a long way from Guantanamo Bay. We go to the local shops, and people smile and honk their horns at him. A woman hugs him and says that every day she prays for his son. He has become a celebrity and the goodwill is palpable, although when Moazzam was first arrested there was some hostility towards Azmat and his family.
He tells me of a woman he met in New York whose son was sent to Iraq to fight. He was young, had only just joined the army and had had very little training. When he got to Iraq he was deployed to defuse bombs and was killed in an explosion. 'She was so sad,' he says. 'These so-called sophisticated governments who preach humanitarian values - they act like cruel barbarians.
'I just want simple human rights and justice. Recently when I have been speaking to large crowds of people I have asked, "Am I right or am I wrong?" Overwhelmingly people have told me I am right. I have been amazed at the response wherever I have gone, but Bush is the military dictator of the world. It is not just my son in Guantanamo. There are a lot of sons there.'