Four men deprived of their liberty for four years on suspicion of being international terrorists disclose today that they have not once been questioned by police or security services since being arrested.

The four, who were among 16 suspects detained without trial under post-11 September terror legislation, later overturned by the law lords, give harrowing accounts of the treatment they have suffered. All are now under virtual house arrest. Although three face deportation, The Independent has learnt that there is no prospect of the men ever being questioned over the offences they are alleged to have committed.

In interviews with Amnesty International, the four - three Algerians and a Palestinian - say their detentions have harmed their physical and mental health. They also complain that their treatment has had a devastating impact on their wives and families.

The men were interned in Belmarsh jail in south-east London - which has been called Britain's Guantanamo Bay - and other high security prisons in conditions consistently condemned by human rights organisations. Their detentions were ruled illegal by the law lords a year ago and they have since been released on control orders with tough restrictions on leaving home.

Three were re-arrested in August under immigration powers pending deportation and released by the Special Immigration Appeals Commission Act (Siac) in October on very strict bail conditions amounting to house arrest. One of them told Amnesty: "We've been moving from one nightmare to another."

Kate Allen, the director of Amnesty International, met the Palestinian Mahmoud Abu Rideh and an Algerian man known as "H" at their homes in the past month and spent about an hour with each of them, together with their wives. She said: "Both men expressed a profound sense of injustice that their liberty had been taken from them without their ever being charged, tried or shown any evidence against them. Both expressed amazement that this could happen in a country like the UK.

"But what struck me most was the impact that the detention and subsequent house arrest of these men has had on their partners and their families. Abu Rideh's house doesn't feel like the kind of bustling home you would expect of a family with five children. It is silent, sad and isolated. Friends and family are scared to visit - to do so they have to submit their name and photo to the Home Office, and in effect become a "known associate of a terrorist suspect".

The disclosure that the men have not been interviewed by the authorities will embarrass ministers, who have claimed that the men present such a terrorist threat that they have to be permanently monitored.

In a report today on the plight of the so-called Belmarsh detainees, Amnesty calls for charges to be brought against them or for the restrictions on their freedom to be lifted. A spokesman said: "Is this really what we call justice in this country? These men have had their liberty taken from them for four years yet they haven't even been charged and tried, let alone found guilty of anything. What's really shocking is that these men, supposedly 'suspected international terrorists', have never once been questioned since their arrest."
The four - Abu Rideh and the Algerians, known as "A", "G" and "H" - were interviewed by Amnesty. All complained of mental health problems including depression and said that their transfer from jail to house arrest had prolonged their ordeals.

"A" said: "I am basically locked up at home for 24 hours a day ... the pressure of this situation is enormous on my family."

"G" complains: "Although I have access to my garden (albeit for a limited portion of the day) I fear that if I reply to any one of my neighbours saying 'hello' to me I will be in breach of my bail conditions. So, I don't even go out in the garden. Every night I fear that the police will come and arrest me again. I feel like I have lost all access to a normal life." Abu Rideh, who has made at least four suicide attempts, says: "I can't sleep. I spend all my time in the house. I don't go outside much; I'm just not up to it."

A Home Office spokesman said last night: "Obviously bail conditions are set by Siac that are considered necessary to address the risk of absconding and to protect national security."

The spokesman did not deny that the detainees had never been questioned by police over the past four years. He said: "We never discuss individual cases." However, one security source said: "We believe these men are dangerous, but they cannot be prosecuted. Under those circumstances there's little point interviewing them."

But Mark Oaten, the Liberal Democrat home affairs spokesman, said: "The fact that no questioning has taken place since arrest suggests that little effort has been made to explore the possibility of criminal charges. If that is the case it is completely unacceptable ... These men have been left in a legal limbo which is contrary to every tradition of justice in this country. Indefinite detention has taken an appalling toll on their mental health, just as it has with the Guantanamo Bay prisoners."

Amnesty is calling for immediate action: "If there is evidence against them, they should be charged with a recognisably criminal offence and tried in a British court," said Ms Allen. "Both expressed a wish for fair treatment, not special treatment - that the authorities should show them whatever evidence has condemned them to this limbo, and give them a chance to refute it in court. All they want is justice."