Lima police video footage shows Michaella McCollum, left, and Melissa Reid during an interview at the airport. Photo / via video

Book extract by Michaella McCollum

The voice is urgent. "Michaella, look out!" I turn my head just in time to see the blade - a kitchen knife, gleaming, unmistakably sharp and destined for my head. I freeze and close my eyes. Stupid, but it's instinct. I'm terrified.

Then there's a scream, a blood-curdling one. But thankfully it doesn't come from me and I open my eyes just in time to see my would-be killer wrestled to the floor by a fellow prisoner.

I know the woman with the knife in her hand: it's Danielle, a Brazilian woman who is mentally ill. Her problem with me? I've changed the channel on the TV.

I'm not her first target and I won't be her last. After all, life is cheap here in Ancon, a bleak modern prison in Peru.

What does it matter to Danielle if she kills me? She's in here for life anyway.

Ancon is one of South America's maximum-security jails. Drug abuse, hunger and violence are rife. Mosquitoes are everywhere. The sanitation is unspeakable. So how on earth did I, a 20-year-old woman from a market town in Northern Ireland, wind up here in a filthy cell in the shadow of the mountains near Lima?

The answer lies in the £1.5 million of cocaine I was caught trying to smuggle out of Peru.

Was I guilty? Yes. Did I know what I was doing? Sort of.

Was I hung out to dry by a bunch of gangsters and the Peruvian justice system? Absolutely. So why did I do it? Why did I jeopardise everything and bring untold heartache to my adored family for a few easy quid?

A one-way ticket to Ibiza

It all started in June 2013 when I booked a ticket to Ibiza, the beautiful but notorious party island off the coast of Spain. I was desperate to escape my hometown of Dungannon - to get away from a complicated relationship with my absent father, from an abusive boyfriend and from the unrest and violence that still blights lives in places like this. I didn't have a long-term plan, just a one-way ticket out.

True, the omens were bad. On the way to the airport I found I'd left my passport at my sister's house, so back we raced. Later, she asked if I'd printed out my boarding pass. I hadn't. I was fined for that, and for my overweight suitcase. I should have changed my plans there and then, but the truth is I'd have boarded the plane even if its wings were on fire.

Once in Ibiza, I found myself an apartment and a couple of bar jobs and, within days of arriving, I was swept up in the island's party lifestyle. At first I just wanted enough money to pay my rent, but I soon realised that most of the people around me, workers and holidaymakers alike, were off their heads on drugs.

One of my jobs included waitressing. But it wasn't just drinks I was serving. Customers would ask for a round of gin and tonics with a side order of cocaine or ecstasy. We'd put the request through to the bar as if it were the most normal thing in the world. And in Ibiza, it was.

The waiting staff were on commission, so the more powders and pills we shifted, the higher our wages. However stupid it seems now, it was seductive. And it wasn't long before I was on the same diet of drink and drugs as the party-going customers. I should say that however wasted I got, I always remembered to text my mother - once in the morning and once at night. That was our deal.

Obviously I didn't tell her a fraction of what was going on - she just needed to know that I was happy and safe. And for a few short weeks, I was both.

I was out with friends one night when a Cockney guy pulled up on a motorbike and took a shine to me. He said his name was Davey.

"That's someone you wanna steer clear of," a friend warned me. "He's a drug dealer." But I paid scant attention. Then I bumped into him again soon afterwards. We chatted about clubs and pills and he began confiding in me about how he made his money. Davey said he liked the lifestyle it brought him and clearly took the view that an honest day's work was for mugs.

At some point he asked me if I fancied doing a "run" - nipping over to the mainland and bringing back drugs for him. I refused, almost insulted that he would ask me such a thing. But he dangled the fact that he'd pay me really well, and the thought must have lodged somewhere in my mind. Whatever words came out of my mouth, the truth is I was tempted. Bar wages were fine and I was having a good time but I felt I needed more than that.

Wherever else I went when the season was finally over, I was determined that it wouldn't be back to Dungannon. I saw Davey again when he held a barbecue. No sooner did the burgers go on, than the drugs came out. Davey came up to me and quietly said: "How would you like to go to Barcelona?"

"Wow," I said. "Sure."

"Not with me, though," he said.

"Then what for?" I was too high to care about the answer.

"I've got a package there that needs lifting."

"Oh," I said, remembering his previous offer. "Is it urgent?"

"Fairly."

He was asking me to collect a consignment of illegal drugs, yet I didn't think too much about my reply. It must seem odd that I was even considering it but, right then, drugs were a normal part of daily life and I barely considered them to be illegal. I was a young woman living far away from home, my family - and from reality. "Go on then, Davey," I said. "Why not? I'll do it."

'There's been a change of plan'

On August 1, 2013, my fate was sealed. That was the day I was introduced to an associate of Davey's called Mateo, a tall, skinny guy from Colombia. "There's been a change of plan," Mateo told me. "You're not going to Barcelona any more. You're going to Peru."

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People will have their own opinions of me for everything that's happened, and what I'm going to admit now is only going to give them more fuel. But the sorry truth is I had no idea where Peru was. No clue. I thought it was another Spanish town.

"I don't want you to worry about anything," Mateo was saying.

"One of my guys will be with you all the way. Planes, buses, hotels, you'll have a pair of friendly eyes on you. You won't know who it is or where they are, but trust me, they're there for you."

"In fact," he continued, "because this is your first time, you won't be travelling alone. Another girl will be with you. You will meet her soon, in Majorca."

Mateo smiled. "Now, here is the important thing. When you pick up the package you will put it in your case and you will go to the airport in Peru. You will go through customs as normal and, I swear, nothing will happen to you."

The officials, he said, were bribed - and I believed him. But then I'd have believed in flying space monkeys at that point.

"The security in Peru have a photo of the other girl, so they know who to wave through," he continued. "Your suitcase will be searched by one of my people and they will find nothing. So you'll just get on your plane, fly here, hand over the package and I will give you five thousand pounds."

Holy Christ. For the first time in 24 hours my brain flickered into activity. Five thousand pounds! Was I hearing straight? I texted my sister and said I was going to Barcelona for a few days and so might be out of contact due to the "partying". I left it to her to translate my message into words my mother would understand.

At the airport I heard a woman's voice speaking English.

"Hey, are you the girl?"

The woman was wearing shorts and a bikini top and she had a great tan - impressive for someone with a Scottish accent. Her look said "beach" but her manner said "office". "Are you Mateo's girl?" "Yes." "I'm Melissa," she said. "Come with me."

Melissa told me that she would be going to Peru a day ahead of me. "Then we've got a couple of days doing all the tourist sites. Machu Picchu and all that." "We're not going there to be tourists," I said, confused. "Davey said I'd be back in Ibiza in two days."

Melissa laughed. "You can't get to Peru and back in two days."

Jesus, I thought. Spain's not that big. But I didn't think to argue. I wasn't sure I liked this woman. I just let her babble on with her itinerary. But after a while, a sense of nagging dread came over me. What had I got myself into?

While we waited for our flights we were staying in the family home of one of the guys involved. We were watched like a hawk by a man called Julio. One afternoon he went out - just for an hour, but it gave Melissa and me the run of the house.

As soon as I met Melissa, I knew she was cocky, confident and a bit of a know-it-all. She obviously got a kick out of being the one in charge and I was happy to leave her to it. So when I suggested searching the place, I thought she would be too uptight to join in, but I was wrong.

I don't know what we expected to find. It certainly wasn't a drawer full of passports and phones. And guns. Guns! I didn't know what to say. Melissa didn't either.

In our wildest dreams neither of us could have envisaged ending up here, in a domestic house, a family home where people kept weapons in their wardrobes. It was terrifying, but I didn't see a way out. I had to carry on with the plan.

Melissa flew out on Monday, August 5, and I followed the next day. I still didn't know where Peru was, but I guessed it was on the opposite side of Spain from Barcelona because of the time the flight was taking. Yes, astonishing as it sounds, I was that naive.

After five or six hours I got super-twitchy. I leant over to the guy next to me and started fishing for information. I asked what he knew about the airport we were heading for.

"Jorge Chavez?" he said. "Not bad. Fairly modern."

"Have you been there before?" I asked. "Lima? A couple of times."

"What's it like?"

"It's like the rest of South America," he said.

"There's poverty and riches right next door to each other."

We chatted some more, but only two words had sunk in: South America. How the hell had I got roped into that? My family would go mental if they knew I'd left Europe. I was starting to panic.

It was a relief to hear a shout at the airport and see Melissa marching towards me, as annoying as she had been back in Majorca. For all her badass bravado, she didn't look too unhappy to see me either.