Brush in hand, she knelt down to scrub the filthy communal toilet she shared with the five other women in her cramped cell.

With the bleak concrete of the walls reflecting the sweltering heat of the South American summer and the bare windows taped up to keep out mosquitos, the smell was revolting.

Never had the easy comforts of her suburban up-bringing seemed so distant.

Now safely back home in Scotland, Melissa Reid has spoken candidly about being locked up in Peru, describing – but absolutely refusing to criticise – the bleak realities of her life behind bars.

Force: Drugs mule Melissa Reid revealed that, in her darkest hours in Peruvian jail, she was almost overcome by her ordeal - but insisted she has no right to complain about the conditions as she was there for a reason

Over three years she experienced the full range of the country's penal institutions: from the maximum security police holding area – where officers sang her Happy Birthday when she turned 20 – to the overcrowded inner-city jail, Virgen de Fatima, where disease is rife, to Peru's notorious Ancon 2 prison deep in the desert.

In her darkest hours, she has revealed, she was almost overcome by her ordeal: especially the bewildering alienation of being unable to understand a word of the Spanish being spoken all around her.

As days, weeks and months dragged by to the monotonous rhythm of the prison regime, she felt worn down by the blandness of the diet, the lack of privacy, and the constant wariness in the company of other inmates.

There were some dark, dark days in there. You can't escape your thoughts. I tried to fill my time but you still have a lot of time to think and a lot of guilt to deal with Melissa Reid

Above all, she has said, she was tortured by how much she missed her family and by the 'dark truth' which was rammed home at every session with the jail counsellor: that she was the victim of her own stupidity; that this was all her own fault.

Speaking last night from her kitchen table at home in Lenzie, surrounded once again by the family whose support kept her strong, she said: 'Prison didn't break me but I saw it break other girls. It was sink or swim and I chose to swim.

'Peru is a poor country and the conditions in prison were very basic but I have no right to complain about them. I was in there for a reason.

'I am very lucky that I have such a supportive family who would take my calls at any time of the day, whenever I was feeling at my worst.

'It wasn't the cold showers or the heat in the cell or the basic food or having to clean the communal toilet, it was being separated from my family.

'There were some dark, dark days in there. You can't escape your thoughts. I tried to fill my time but you still have a lot of time to think and a lot of guilt to deal with.'

Behind bars: More than anything, says Reid, she was tortured by how much she missed her family and by the 'dark truth' which was rammed home at every session with the jail counsellor: that she was the victim of her own stupidity. Pictured, Reid during a court hearing at the Callao courthouse

Haunted: Over three years she experienced the full range of the country's penal institutions: from the maximum security police holding area, to the overcrowded inner-city jail, Virgen de Fatima, where disease is rife, to Peru's notorious Ancon 2 prison deep in the desert. Pictured, Reid in Ancon prison

In May 2014, as she and Michaella were finally starting to find their feet inside Virgen de Fatima women's prison, they were moved without warning to Ancon 2 – a maximum-security 'concrete jungle' built into the hillside more than an hour outside Peru's capital.

They spent the next two years locked up in the female wing, where, Melissa, said: 'you have to watch your back at all times.'

I was quite mouthy at the start and stuck up for other people when they were getting a hard time but I quickly realised it was pointless and that I had to toe the line Melissa Reid

She said: 'There is a constant atmosphere inside and you know you need to keep your head down. In that environment anything can happen and there is a lot of jealousy. I was constantly looking over my shoulder.

'People knew who I was and where I had come from and how my family were sending things to help me – even some of the guards were jealous and would make things more difficult.

'I was lucky that nothing bad happened to me. I was quite mouthy at the start and stuck up for other people when they were getting a hard time but I quickly realised it was pointless and that I had to toe the line.

'It was hard at the start as the guards all spoke Spanish and we didn't know what was going on. That spurred me on to learn the language as quickly as I could and I became fluent.'

To earn extra money, inmates are encouraged to work and make things to sell to the outside world. Melissa began knitting but soon found her needlework was not of a high enough standard so she moved on to making shoes and bags.

Upset: In May 2014, as Reid and McCollum were finally starting to find their feet inside Virgen de Fatima women's prison (pictured), they were moved without warning to Ancon 2

Time: To earn extra money, inmates are encouraged to work and make things to sell to the outside world. Melissa began knitting but soon found her needlework was not of a high enough standard so she moved on to making shoes and bags. Pictured, the notorious Ancon 2 prison in Peru

'The goods are sold outside and groups also come into buy them. People make clothes and shoes and bags and crafts.

'Other girls learn how to do hair and paint nails. You do what you have to do to survive.

JAILED, BUT NO CRIMINAL RECORD Despite being convicted of drug trafficking, Melissa Reid will not have a criminal record in the UK. In December 2013 she and co-accused Michaella McCollum were jailed for six years and eight months after being caught with 24lb (11kg) of cocaine at Lima’s Jorge Chávez International Airport four months earlier on August 6, 2013. However the crime will not appear on employer background checks - and even advanced searches for people hoping to work with children and vulnerable people will be clear - because it took place outside Europe. Co-accused: Michaella McCollum in August 2013 There is no set agreement between the British authorities and foreign nations to share records of convictions. However Melissa would be well advised to come clean with potential employers as employment law states that a job applicant can faces dismissal if they are not honest about convictions when explicitly asked. Meanwhile Melissa’s co-accused Michaella remains in Peru. While Melissa applied for expulsion from Peru under new laws designed for foreign prisoners, Michaella, 23, opted to leave jail sooner under the country’s parole system and remains in Lima. Michaella from Dungannon, County Tyrone, is currently living in an apartment in the upmarket Barranco district of the city after being released from Ancon 2 at the end of March on Semi Libertad - which means she is free from prison but must check in with the authorities and cannot leave Peru. The MoS understands Michaella has now applied to return home under the expulsion law and will face the same judge who freed Melissa in the coming weeks. Both young women initially applied for repatriation under a prison transfer agreement, which would have seen them forced to spend time behing bars in their home countries. Advertisement

'It's a strange situation and people definitely take advantage of the girls in there by having them make stuff for not much money.

'The basics you are given are very basic so you need money to buy more.

'For breakfast they give you bread and a hot drink. Lunch is the main meal – you get rice and beans with no sauce pretty much every day – and for dinner you get a maize pudding with some pineapple.

'Twice a week 'package women' come in selling vegetables and other luxuries and I made sure I always bought some to try and keep healthy. They cost a lot more inside the prison than they would do outside.

'We would be given a 15 minute slot to leave our pabion (cell block). They shouted 'tuck shop' and everyone rushed out in a swarm.'

The desperation of some of her fellow prisoners, who did not have the luxury of money sent from home, was also clear on visiting days – when local men would come in and 'try their luck'.

She revealed: 'On visiting days you would get Peruvian guys coming in to try their luck and meet girls, particularly European girls with fair hair and blue eyes.

'I didn't get involved in any of that but there are some girls who are vulnerable and need money so they get involved with these guys. You can't have sex in the female prison but you are allowed to kiss in the visiting area.'

She added: 'There are also religious groups who come in and say they want to help the girls and buy their stuff. You find girls from Thailand who are Buddhist going to the Jehovah's Witness meetings because they need to make money.'

While inmates are not made to wear a uniform, the dress-code is strict. Melissa said: 'You can't wear black as that is what the guards wear and you can't wear red.

'They also don't like it if you wear anything they see as revealing such as a dress or shorts, even on a really hot day.

'The windows just have bars, no glass, so it gets very very cold in the winter. We taped them up but that meant in summer it got hot and germs spread. I have picked up a lot of coughs and colds.

'People are allowed to smoke inside the prison and the corridors are thick with it. I found that tough every day.'

They were all made to do their own laundry and keep their cell clean, with little resources.

Melissa said: 'we had a system for cleaning as best we could. The toilet can get disgusting but we tried to keep the cell as hygienic as we could.

'You have to wash your own clothes in cold water. A lot of the girls used the sinks but it was very unhygienic so I managed to get a basin to use. I washed my underwear in the shower.

'You are allowed to use the microwave for three minutes each day. At the start we used it to boil our water to ensure it was clean but that meant we couldn't use it for other things. They are strict like that.

'The lights would blow a lot and we would be left in darkness but they would blame us for plugging in our electronic devices.

'At night when we were locked in we had to make sure we had bottled some water in case we got thirsty in the night.

'It frustrated me that I was living in a cage but I got on with it.'

The stresses did affect the young woman physically but she saw others fairing worse.

Busted: Melissa Reid and fellow drug mule Michaella McCollum Connolly were caught carrying more than a million pounds' worth of cocaine in their luggage, stashed in food packages and wrapped up in clothes

'While I was in Ancon prison there were a couple of suicides. We didn't see them but we knew it had happened.

'There are a lot of people who have HIV and are very sick, which was hard to see. The medical care is basic.

'The stress of what had happened meant my periods stopped for a full year. It was quite worrying and they finally brought in a gynaecologist for me.'

Looking back, she said: 'You get through it all because there is a sisterhood. You get each other through it.'