Even by the standards of Callao - the crime-ridden port district of the Peruvian capital Lima - the neighbourhood around Sarita Colonia prison is particularly dangerous and poor.
Behind the puce green walls topped with razor wire and gun turrets, some 2,500 men live inside the prison which was designed and built for just 500.
At least a fifth of them are non-Peruvian, and almost without exception all have been jailed on drug trafficking charges.
Most inmates are Spanish or Dutch, but the number of UK citizens is increasing rapidly.
There are 42 British prisoners in Peru - the largest number in any South America country.
Apart from its famed tourist attractions, Peru now rivals Colombia as one the world's top cocaine producers and it is estimated the country is now the source of around 60% of the drug in Europe.
Nick Jones from west London, described his reaction at being caught at trying to smuggle nearly 2kg of cocaine out of Peru's International airport in Lima as "very surprised".
He was arrested in April 2009.
"I was told that everything was taken care of, that the airport security had been paid in order to let me through," he said.
"I believed those lies so I thought it would be plain sailing."
But Nick's illusion of easy money soon came crashing down.
He said: "There is no such thing as a quick buck. They will tell you that the airport security has been paid off but all they are trying to do is get one out of 10 to come through for them and they've made their money.
"They don't care about the nine that go to jail."
The 34-year-old now faces the standard sentence of six years and eight months for trafficking any amount of cocaine under 10kg.
He describes his experience of Peruvian prison as tougher than he ever could have imagined.
Nick's jail time will be harder still because his family is so far away and he is short of money. He relies on 350 Peruvian Soles ($125) given to him every three months by the Prisoners Abroad organisation and delivered through visits by British Embassy officials.
But he is denied even this small amount: "It's impossible for me to keep it because as soon as I come into the pavilion there are people who know that the embassy has brought money and they will be demanding it from me."
While the prisoners in effect run the understaffed prison, the officials also collude in the corruption, he says. He claims he and other prisoners are charged entry fees and even for the upkeep of the prison.
"This hell hole is not a jail, it's a business - it is just about making money," he claims.
Some foreign prisoners are released early on probation, but have to remain in Peru while not legally being allowed to find a job. It is not a prospect which he relishes.
"Being stuck here after the years I've spent inside in hellish conditions without being able to work? What kind of justice is that?" he says.
He says the hardest part of all is the day-to-day survival in jail.
Nick says the overcrowding is so severe that he finds it extremely difficult to sleep as he and fellow inmates are crammed together "like sardines" in a pavilion which is fit to bursting.
With some 350 people crammed into a space for 70, he says "every time someone moves or sneezes there's tension, sometimes violence".
"The food is literally inedible," he adds.
"They bring you food with stones in it, or used toilet rolls. If you try to live on this food you will permanently suffer from diarrhoea and stomach sickness."
James Brokenshire, the Home Office minister for Crime Prevention who has been visiting the region, saw first hand the conditions in which the British inmates are living in Sarita Colonia jail.
"The liability that you will be caught is very, very high," he told the BBC.
"The prisoners said to me that they'd like to get that message back so that through their experiences people won't make the choices and the mistakes that they've made, because being here is no easy ride."
The minister is helping to encourage more cooperation between the UK and the authorities in countries like Peru to tackle the cocaine trade.
"It's shared problem because of the problems posed here [in Peru] as well as the social breakdown, the addiction and crime issues it causes in the United Kingdom," he said.
The UK is the largest single cocaine market in Europe, closely followed by Spain, according to the UN's 2010 World Drugs Report.
In contrast to the shrinking market in the US, the number of users in Europe has doubled in the last decade to more than four million.
Meanwhile, Nick Jones would do anything to turn back the clock.
"The stress and the strain of being in a situation like this when you can't sleep, you don't eat, you can't drink the water is very, very hard.
"I would say to anyone thinking of doing what I did, think again, think again and look for a better and legal way to make the money that they need."