The drugs trade in UK prisons is estimated to be worth £22m a year
Tony has spent 11 of the past 16 years in prison, with 10 of those addicted to heroin, a habit he picked up while inside.
"Time became irrelevant," said Tony, aged 31, of the drug's allure. "If you had enough heroin your sentence would fly by."
But what started out as an easy distraction, that he tried for the first time in jail, became a habit that in turn kept Tony passing through the prison's revolving doors for years.
Drug addiction is often the root cause of crime in the UK and figures from the Ministry of Justice show £100 million is spent on drug rehabilitation programmes in prisons every year.
There are no official figures, but one senior Prison Service source told Panorama, it is estimated that the drugs trade in jails across England and Wales is worth an annual £22m. Others say it could be four times that amount.
Tony said that drugs were part of the scene from his first days in a young offenders institute.
I had to brew alcohol in prison to pay off debts. I got beatings because I'd not paid debts in time.
Tony, former prisoner
Serving his first sentence at 15 for stealing cars he found cannabis was rare but available. By 17 he was sharing a cell with a heroin user.
"It was his first night and he had some with him. He had smuggled it in and I tried it then."
Later, in adult prison, Tony found heroin was rife. "I could buy it every day if I wanted," he said.
In a cash-free society money can be transferred between bank accounts on the outside, or inside the prison, mobile phone top-up cards are a valuable currency. Although mobile phones are banned in prison, like drugs they are routinely smuggled in helping inmates organise their drug drops. Drugs are then smuggled in to prisons in various, sometimes highly creative, ways, Tony explained.
He had heroin brought in by visitors, delivered to him through the post where it was stitched into clothes or stuck into an 'I Love You' card between the peeled back sheets of the card.
Heroin is called "bird killer" by inmates who use it to help pass the time
Tony would carry his wrapped heroin in his anus to avoid detection but was found positive through random drug testing. An extra 14 days were added to his sentence, but he said the random testing is part of the problem.
Since their introduction in 1996, the Prison Service has reported a two-thirds drop in positive tests from almost 25% to around 9%. But some prisoners say the tests have pushed inmates onto harder drugs as they try to avoid detection. Cannabis stays in the system for 28 days, whereas heroin can be detected for just two or three.
Panorama has been given exclusive footage of drugs being smuggled into prison by visitors.
"For people serving big sentences it makes sense to do heroin as it is out of your body quicker," Tony explained. Heroin also comes in smaller packages, making it easier to smuggle.
Phil Wheatley is head of the Prison Service and acknowledges there are concerns about mandatory drug tests but denies the prisoners' claims.
"Some outside experts have said it would induce switching to opiates. Actually the independent research has shown that that doesn't happen at scale at all, it's not a risk," he told Panorama.
But detection is not the only threat.
"My mate got his face slashed over it down to the bone. I've never seen anything like it," said Tony as he recounted an attempt by one inmate to steal a package of heroin. Threats and bully tactics go with the territory and, as in the outside world, money is often the cause.
"I was in debt every week. I went into prison with £60 and within two days I was £80 in debt and you cannot get out of that debt.
"I was having to borrow off other prisoners to pay it off so the debt would spiral. I had to brew alcohol in prison to pay off debts. I got beatings because I'd not paid debts in time."
His addiction followed him into life on the outside and he was soon committing crimes to feed his habit that would see him back behind bars. His last stint in prison was for breaking into a house and stealing a car. Drunk at the time, he crashed the car and broke both his legs.
An estimated 55% of prisoners enter jail with a serious drug problem
Over £6m a year is allocated by the Prison Service to disrupting the drugs supply chain
Over 4,000 mobiles and more than 4,000 SIM cards have been seized in prisons in England and Wales in 2008-09
Source: Ministry of Justice
This time, Tony got help. Through a 12-step programme run by the Rehabilitation of Addicted Prisoners Trust (RAPt) he was helped on the road to recovery. This week he celebrates 14 months of being clean, and his longest stretch out of prison since he was 15.
"I'm living life day by day. I'm feeling really good but I had to go through a grieving process."
Breaking the cycle
Supported by the RAPt aftercare team, he also regularly attends Narcotics Anonymous and now lives in a dry house with eight other people. He seems determined to stay on the wagon.
"When I lost the obsession to use I could have kicked myself," he said.
"I thought I was an evil person but I have been able to separate from the guilt and start to recover."
His mentor has been clean for 10 years. As Tony put it, "he must be doing something right."
Tony is now mentoring a man just out of prison and speaks to prisoners in rehab about his own experience.
His story of life inside the system reveals the cyclical nature of the problem of drugs in Britain's jails. Almost 5,000 drug seizures were made in prisons across England and Wales last year illustrating the scale of the problem.
As Tony says, "Prison is like a little community. You see the same faces in and out and we all seem to get on the heroin. It's all about the drugs."
Panorama: Smugglers' Tales is on BBC One, Monday 3 August at 8.30pm
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