Enemy Combatant, by Moazzam Begg with Victoria Brittain

How do you objectively review a book like this? Moazzam Begg has known Guantánamo Bay and come out to tell us the tale. Survivors of concentration camps have a central place in Western iconography, and in human history. Begg does not have the philosophical depth of Primo Levi or Rabbi Hugo Gryn, but he writes with the same authenticity and conveys horror without hyperbole.

He recollects first impressions of his hi-tech Cuban coop, covered with "a pale green steel mesh, doubled, with one part of the mesh set vertically and other horizontally, so they crisscrossed one another". He was "in this steel cage with mesh round its sides, steel roof and floor, steel bed, steel toilet, all inside a white, new-looking brightly lit room". The devil is indeed in the detail provided by Begg, who endured three years of brutal incarceration and was able still to think, argue, observe and record the external and internal chaos.

A former law student, this bearded Brummie has an indestructible soul that you feel as you read his account. All you want to do is welcome him back, hug his book and punish his tormentors. You rage for him and the others; you are overcome with humility.

But yet, but yet... such a rare testimony demands dispassionate scrutiny, if only to disable the US authorities who want to insinuate that these former prisoners cannot be trusted. If the world was allowed to know the objective truth, the Republican regime could not play these games and we could properly assess the claims of inmates.

For four years, various journalists, writers and activists have tried to keep awake the conscience of the West, to remind decent people of the satanic pit of Guantánamo Bay. The most powerful and God-fearing democracy in the world sweeps up Muslim men it suspects of being terrorists, drugs, shackles and transports them to a site beyond jurisdiction. Hundreds of the living dead in orange uniforms are labelled "enemy combatants", a category as obscenely meaningless as any that Stalinism came up with.

The few men like Begg eventually released (without being charged, without apologies, without recompense) talk of beatings, isolation cells, forced feeding, death threats and witnessed murders. It is all justified with the same refrain: were not over 3,000 US nationals and residents blown up by Al-Qa'ida in 2001? How much global anguish and bloodshed will appease those poor dead souls?

In US-controlled detention centres across the world, individuals instructed to obey orders are often less sure of the Republican regime's aggressive mission. The best parts of Begg's book are those which humanise these operatives and attempt to understand their confusion and corruption. He sees the absurdity of their situation and is precise and unsentimental when he describes his own life, as he grew up in Britain trying to integrate disparate identities.

I met Begg's father after a performance of the play Guantánamo: Honour Bound to Defend Freedom, scripted by the co-author of this book, Victoria Brittain, and the novelist Gillian Slovo. In spite of his anguish he kept his iron will steady. His boy is made of even sterner stuff but does tend to make fast and fiery attachments to various good and dodgy Islamic causes.

His adventures abroad remain half-explained and, for a man of intellect and deep faith, he does at times appear perilously impulsive. The bulk of this book, though, is a stirring indictment of Bush, Blair and their sordid politics. I suggest readers should buy a copy and post it to our righteous PM. Bagfuls of Beggs pouring into 10 Downing Street - now there's a thought.

Yasmin Alibhai-Brown's one-woman show, 'Extravagant Strangers', is now at the Soho Theatre