Shaun Attwood was a British drug dealer who spent two years in one of America's most notorious prison systems. Now he tours British schools to warn about the dangers of drugs. But how confident is he that children will learn from his mistakes?
From a "cockroach-infested" jail cell in the desert to the school classrooms of Britain's shire counties, Shaun Attwood's past eight years have been characterised by contrasts.
In December 2007 the Widnes-born former stockbroker emerged from one of the most notorious jails in the US, was deported back to Britain and set about writing a memoir.
Hard Time: A Brit In America's Toughest Jail is a searing indictment of the controversial penal tactics of Sheriff Joe Arpaio - who revels in the title of "America's Toughest Sheriff".
But it is also an account of how a young British man got sucked into America's gang-dominated illegal drug enterprise - and ended up having to pay a high price for the riches it brought him.
Sheriff Arpaio's system of law enforcement, which extends across a county of Arizona, has for some years divided opinion in the US and overseas. It has involved inmates being forced to wear pink underpants and women being put on chain gangs, while the sheriff has bragged that it costs more to feed the guard dogs than the prisoners he oversees.
For Attwood, who was unaware of the sheriff's regime until his arrest in 2002, it was rude awakening from the luxuries of his drug-financed lifestyle.
Having been rejected by several City of London stockbroker firms, he arrived in Arizona in 1991, equipped with a degree in business studies and a fake work visa.
He began working as a stockbroker. But Attwood, who had been involved in the rave scene back in England, drifted into the drug dealing business.
Initially, he says, he was simply buying supplies of ecstasy for raves.
"We did enough drugs to kill a herd of elephants," he quips, referring to his own consumption habits.
But by the late 1990s he had become a large-scale dealer whose main competitor was a former New York gangster who had been relocated to Arizona by the FBI after testifying against a Mafia boss.
In an excerpt from his book, Attwood describes life at the "peak" of his criminal career: "I had my own rave clothing/music store and LSD chemist. I married one of the most glamorous glitter girls in the rave scene... and we moved into a million-dollar mountainside home in Tucson."
But the express train of Attwood's life hit the buffers on 16 May 2002 when a heavily armed team of police smashed through his front door.
By then he had split up with his wife and Attwood went on to serve six years in prison for money laundering. But it was the first 26 months, while awaiting trial, in Sheriff Arpaio's custody that was the most horrific, he says.
In the book he describes brutality by prison guards, racist gang fights, food which was little more than slop, cells which were overcrowded, airless, unbearably hot and full of cockroaches.
After supporting him for two years his then girlfriend, Claudia, could take it no more and broke up with him.
Attwood described his jail life in a widely read blog and it is this which forms the basis of his 300-page memoir, which in turn informs a talk he gives to school children all over the UK.
He has been speaking at three schools a week and says his story strikes a chord with many children.
"I've had girls burst into tears and one boy fainted," he says of the reaction to his detailed descriptions of prison life.
But is there any realistic hope the youngsters will not repeat his mistakes? After all, British penal regimes are less austere than that of Maricopa county, Arizona.
"It's a certainty that some of those kids will die from drugs and alcohol but if I can make an impression and steer them away from all that stuff then it is restoring my karma," he says.
Attwood says as a child he ignored the warnings about drugs he received at school.
"I didn't take any notice. I was never exposed to anyone like me who could have told them a story that would have gripped me. Drugs start out as fun - that's why people do them - but you need to do more and more and you end up paranoid and out of control."
He remains in touch with many of his fellow inmates and updates his blog with details of their lives inside Maricopa's jails.
As for his allegations about the prison regime, Sheriff Arpaio is defiantly unapologetic. He admits he spends only 50 cents a day per inmate on food, but claims it is checked by dieticians. As for the cockroaches...
"We have pest control people coming to our jails all the time," he tells the BBC News website, "but hey, it's the desert. How do you keep out cockroaches? I've got cockroaches in my house. This is Arizona."