Jamal al-Harith, 37, who arrived home three days ago after two years of confinement, is the first detainee to lift the lid on the US regime in Cuba's Camp X-Ray and Camp Delta.
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A diet of foul water and food up to 10 years out-of-date left inmates malnourished.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.
The full story is on the Mirror website at http://www.mirror.co.uk/news/allnews/content_objectid=14042696_method=full_siteid=50143_headline=-MY-HELL-IN-CAMP-X-RAY-name_page.html
Rosa Prince and Gary Jones (Mirror newspaper)