Construction of Camp Delta began in February last year to cope with the increased number of detainees after the initial detention centre, Camp X-Ray, had proved too small, with its capacity of 320, to hold all the prisoners. Plans are under way to increase the size of the camp to hold more than 800 by the end of the year.

There are 24 detention units in each block at the camp, the units being 2.4m (8ft) long, 2m (6ft 8ins) wide and 2.4m high. Conditions are better than those at Camp X-Ray, with each unit having its own sink, toilet and bed.

Prisoners are entitled to three meals a day, which are described as "culturally appropriate" - offering a diet that does not conflict with the detainees' Islamic faith. Camp officials claim that prisoners have put on an average of about 6kg (13lb) each.

Tight security

Security is so tight that any materials associated with the food that could possibly be used by detainees to create a makeshift weapon are removed by guards and at the end of every meal prisoners have to account for every item connected with the food. One of the reasons given is to prevent detainees from committing suicide.

As well as the 34 prisoners reported to have attempted suicide, more than 80 are said to suffer from psychological problems, mainly depression. Three have tried to hang themselves using home-made nooses.

The prisoners are dressed in orange suits and flip-flop sandals and are each given a pair of shorts because the temperature can reach 38C (100F). They are entitled to two showers a week. The detainees are also allowed a copy of the Koran and a prayer mat; an arrow in each cell points in the direction of Mecca.

The official reason for holding the prisoners at Camp Delta is that they are non-American citizens and that they were members of al-Qaida or have trained with the group. Of the 38 different nationalities, the largest number are Saudi Arabians at around 150, with more than 80 Yemenis and more than 50 Pakistanis.

Despite the official end of hostilities in Afghanistan, there has been a steady stream of prisoners since the camp opened. In June last year there were 536 detainees at the camp, a figure which has now increased to 680. They range in age from a 15-year-old boy to men in their seventies.

Detainees who have been released from the camp - around 35 so far - and returned to Afghanistan have mainly complained about the extreme isolation and the fact that they were often kept with people whose language they did not share.

While there have not been complaints of beatings, those interrogated have said that they were subjected to sleep deprivation during the sessions, which are carried out by intelligence officers from the CIA and the military. Those who misbehave are taken to the "cooler", and if they require medical treatment they are shackled to trolleys before being taken to the medical facility.

The prisoners at Camp Delta are not entitled to access to lawyers or any of the normal legal rights of prisoners. A number of lawyers based in Los Angeles have sought through the courts to gain access to the men to represent them but have been rebuffed.

In the planned tribunals, the prisoners will be given a defence lawyer but not one of their choice and they will be subject to a number of other restrictions: the prosecution lawyers will be entitled to listen in to all discussions between the accused and his lawyer. There will also be no appeal if the accused is convicted.