The father-of-three, from Manchester, told how he was assaulted with fists, feet and batons after refusing a mystery injection.

He said detainees were shackled for up to 15 hours at a time in hand and leg cuffs with metal links which cut into the skin.

Their "cells" were wire cages with concrete floors and open to the elements - giving no privacy or protection from the rats, snakes and scorpions loose around the American base.

He claims punishment beatings were handed out by guards known as the Extreme Reaction Force. They waded into inmates in full riot-gear, raining blows on them.

Prisoners faced psychological torture and mind-games in attempts to make them confess to acts they had never committed. Even petty breaches of rules brought severe punishment.

Medical treatment was sparse and brutal and amputations of limbs were more drastic than required, claimed Jamal.

A diet of foul water and food up to 10 years out-of-date left inmates malnourished.

But Jamal's most shocking disclosure centred on the use of vice girls to torment the most religiously devout detainees.

Prisoners who had never seen an "unveiled" woman before would be forced to watch as the hookers touched their own naked bodies.

The men would return distraught. One said an American girl had smeared menstrual blood across his face in an act of humiliation.

Jamal said: "I knew of this happening about 10 times. It always seemed to be those who were very young or known to be particularly religious who would be taken away.

"I would joke with the other British lads, 'Bring them to us - we'll have them'. It made us laugh. But the Americans obviously knew we wouldn't be shocked by seeing Western women, so they didn't bother.

"It was a profoundly disturbing experience for these men. They would refuse to speak about what had happened. It would take perhaps four weeks for them to tell a friend - and we would shout it out around the whole block."

Jamal added: "The whole point of Guantanamo was to get to you psychologically. The beatings were not as nearly as bad as the psychological torture - bruises heal after a week - but the other stuff stays with you."

He was talking from a secret location after being reunited with his family. The website designer, a convert to Islam, had gone to Pakistan in October 2001, a few weeks after September 11, to study Muslim culture.

He accidentally strayed into Afghanistan - believing he was being driven to Turkey - and was arrested as a spy, perhaps because of his British passport. He was held in Kandahar, Afghanistan, and fell into US hands.

Now Jamal bears the scars of Guantanamo. He stoops into a hunch as he walks because the shackles that bound him were too short.

As a punishment, inmates would be confined so tightly they would be forced to lie in a ball for hours. During lengthy interrogation, they would be tethered to a metal ring on the floor.

Jamal said: "Sometimes you would be chained up on the floor with your hands and feet actually bound together. One of my friends told me he was kept like that for 15 hours once.

"Recreation meant your legs were untied and you walked up and down a strip of gravel. In Camp X-Ray you only got five minutes but in Delta you walked for around 15 minutes."

Jamal said victims of the Extreme Reaction Force were paraded in front of cells. "It was a horrible sight and it was a frequent sight."

He said one unit used force-feeding to end a hunger strike by 70 per cent of the 600 inmates. The strike started after a guard deliberately kicked a copy of the Koran.