MOHAMMED EL-GHARANI, aged 14 and of Chadian parentage, went to Pakistan from Saudi Arabia in 2001 to learn English. Travelling on a Chadian passport with faked personal data facilitated by a sympathetic consular official — he was a minor — he stayed in Karachi with relatives.

His life was organised around English classes, football and prayers until one day, three months after 9/11, he was detained outside a mosque because of his Saudi accent. After a period of incarceration, interrogation and torture by Pakistani security officials he and dozens of others were each sold as “confirmed” terrorists to the US for $5,000.

Naively, El-Gharani believed that US officials would soon realise that he was innocent, release him and allow his return to Saudi Arabia. He had a rude awakening in store.

From day one, Guantanamo was hell on Earth. Most of the guards and interrogators appeared to be sadistic psychopaths seeking gratification in inflicting extreme levels of brutality on the detainees. The regime included rotten food — pork was deliberately served as a humiliation — and bedding was infested with fleas and lice. Showers were permitted once every three months.

But the prisoners soon found ingenious ways to strike back, as when tossing their faeces and urine at unsuspecting guards. A huge black guard they called “Tyson” was supportive and humane but he was a rare and honourable exception.

When El-Gharani was given the hopeful news that Barack Obama is to sign an executive order to close it down  he couldn’t know how hollow the promise was. He was eventually released in 2009 as a result of representations by Shaker Aamer, himself only released in 2015, to Clive Stafford Smith of Reprieve UK.

His health has been ruined by years of torture at the hands of US officials. He suffers from a bad back, has advanced glaucoma and required surgery on his stomach. And it still hurts when he urinates.

Back in Chad, he married and named his first son Shaker after his Guantanamo friend. But he was not to know peace.

Engagingly written by Jerome Tubiana and illustrated with verve and imagination by Alexandre Franc, the book potently visualises what words alone never can. And it demonstrates that if Guantanamo’s aim was intelligence gathering, it was staggering in its ineptitude.

Highly recommended.

Published by SelfMadeHero, price £14.99.