Cecilia met us outside Loki, and from there we followed her to the otherwise typical Plaza de San Pedro, different only for the monolithic building on its east side.

In Cusco, a couple of girls had told us about San Pedro prison.

They said for £60 you can go on a tour around the prison.

It sounded the only opportunity three ponces like us would ever get to see the inside of a prison.

Thomas McFadden, a British drug smuggler started running illegal tours of San Pedro over a decade ago. Aussie backpacker Rusty Young went on to record and recount McFadden’s story in ‘Marching Powder’ after befriending him on one of the tours, then freely spending three months inside with him.

McFadden was released long ago but the tours continue. The attraction is San Pedro is entirely run by its inmates, that guards only enter to take the morning and evening roll call.

Sometimes, you hear the tours aren’t going anymore. We didn’t have any trouble getting inside. Within minutes of arriving in La Paz we’d blundered our way onto one. We said we’d like to go and somebody else handled the rest. I think they asked behind the bar in Wild Rover.

In the Plaza, we’re passed over to somebody else and they instruct us to enter the prison in two’s.

Outside waiting, Bolivian women carrying bundles. We’re escorted right past, and through the small innocuous entrance. In front of us, another gate; this one holding back a crowd of shouting prisoners reaching through its bars toward us like something from Night of the Living Dead.

We’re quickly steered to the right and taken down a short corridor, into a small administration office where we record our names and passport numbers in a register and pay our entrance fee.

Christian our guide presents himself. I figure there’s no issue revealing his name because nobody reads this anyway. Christian was born in Bolivia but has lived most his life in the States. He’d been busted in possession of three grams of cocaine – but it wasn’t his fault!

We need to know who to blame. It’s the government. Way he tells it, he’s the victim of a corrupt system. He reckons $5000 will be enough to bribe his way out and he pitches to us his website through which we can send him money. I’m also pretty sure he’s on coke.

We’re led up a staircase, past prisoners on all sides, into an office, where there are two rough-looking prisoners. These are our bodyguards, both murderers and both serving life.

For murder in Bolivia, you get a thirty stretch, and regardless of what you do in prison that sentence that can’t change. Killers are used to protect tourists because they’re the tangible fear of the entire prison. They can do what they like.

The prison appears the same as the streets outside, just missing the exhaust fumes.

Courtyards are lined by two-story pastel buildings. Laundry hangs out to dry.

The prison has eight divisions. Each division is run like a separate government with elected leaders charging taxes that provide for the greater population. To stay alive, the inmates must make money. So, they open restaurants and shops and offer skilled services. Cons have to buy themselves a flop when they first arrive at the prison, creating an internal property market. When they do, they’re given the key, and contracts and deeds are signed. A bit of dough will get you a plush studio cell with kitchen, bathroom and satellite TV. Some move their families in.

Via narrow alleyways and crowded courtyards, we slide deeper into the prison. The whole time, dodging running kids.

On a second day hangover, everything seems far away to me, as if it isn’t real and just a copy and I’m not really there.

Inmates in the dirty kitchen stir vats of gruel that looks like Ready Brek. We’re offered a taste. In my guts the booze is still putting up a fight so I don’t take any. The gruel is provided by the government, but nobody eats it if they can afford not to.

There is a circular pool sunk into the floor, in another section, about five metres in diameter and empty. It used to be that rapists and paedophiles were trampled and tortured and killed in the pool. Now they all work in the kitchen.

Christian and our bodyguards abandon us to buy drinks and we’re left sitting on little red chairs given to the prison by Coca Cola for exclusive advertising rights, and I feel like an ambulance screaming down a quiet street. A sore thumb. But the cons aren’t interested in us. Most of them look as bored as the ocean.

Besides.

They’re back before we know it.

In the poorest part of the jail, four or five inmates share cells as big as a toilet stall. The only smell is shit. Christian keeps holding his hand out behind him. What he’s trying to tell me I don’t know.

Afterwards, I learn that this is when I’m supposed to tip him. The money from the tours is spread throughout the prison system, with most of it going to the authorities that need to be greased. Tour guides depend on tips to make a living or buy a ticket out of the joint. But if the bodyguards see me give it to him, they’ll want a piece of it too. That’s why he was being all clandestine. Because he’s selfish.

We climb a winding metal staircase to the roof of the block. La Paz stretches out all around us and you can see anywhere to anywhere just by looking.

A prisoner has been following us. Harold Guzman is just about intact. The skin on the inside of his forearms is run from wrist to elbow with pink scars. They say the best coke in the country is cooked inside the prison. The poorer inmates are addicted to its base, better known as crack. To come down, they slice themselves. Guzman gives us each a portrait of ourselves.

I feel about as fresh as an old punching bag as prisoners try to flog me jewellery and homemade ice-cream. The ice-cream is more like marshmallow.

The big finale is we’re taken to a small room. Two backpackers snort lines off a mirror, joking and laughing with a couple of cons.

So there we are declining coke and tea, because nobody feels like sniffing or smoking anything. A couple of people have a beer but with the booze still running out of me I tell them no, so we sit on the bench seats at the table and make small talk with a couple of murderers.

There was a time when you could spend a night here. The best all-night party spot in La Paz, apparently.

It can only be late morning when we run across the plaza to re-enter the outside world.