Image caption Prisoners rioted at Ford Open Prison after consuming contraband alcohol

"On New Year's Eve, a few of the inmates were drinking and an officer arrives and says 'keep the noise down' and at the same time, he smelt alcohol.

"He came out with a breathalyser and tested two of the guys. They were positive.

"The guys turned around and said 'turn a blind eye' because we're having a bit of fun, the noise is going to go away."

Mark, not his real name, recalls the events that took place at Ford Open Prison, in West Sussex, as the first few hours of 2011 ticked by. He speaks in a low whisper, from his cell inside the prison, on a contraband mobile phone he bought from another inmate.

"The officers refused to dismiss the nicking that they [the prisoners] got for drinking so as a result they erupted.

"These guys went to the wing officer to get rid of the evidence. A fire was set alight and before you know it, everyone else joined in and everyone was drunk and rioted. That's it."

An estimated £3m of damage was caused on the night, as several buildings were burned down. In the aftermath, questions were asked about low staffing levels at Ford, where just two prison officers and four support staff had been left in charge of more than 500 men.

But how did the inmates at Ford get hold of the alcohol in the first place?

"Over the fence, obviously, " Mark explains.

"People come and throw it over the fence. They've got CCTV but, you know, once you collect it and you run through the wing it's hard to find any evidence."

Contraband booze

Speaking to the 5 live Investigates programme, another prison insider claims that inmates go on a 'rabbit run', whereby one of the more athletic prisoners will make a dash through a hole in the fence to the local supermarket to buy alcohol for the inmates.

Shorter term prisoners come here and start to erupt because they have nothing to lose because they know they will be released 'Mark', Inmate at Ford Open Prison

This is done between roll calls, when prison officers conduct a register of inmates. The alleged record for this round-trip is just under 30 minutes.

The free availability of alcohol at Ford Open Prison was condemned by the Chief Prison Inspector, Dame Ann Owers, in 2009, who reported "large amounts" of alcohol were not uncommon. Back in 2008, over Easter weekend, staff found 30 bottles of vodka.

But according to current Ford inmate Mark, the real underlying issue is not the free availability of alcohol, but the unsuitability of inmates being admitted to open prisons.

Mark is a long-serving prisoner, and his place at Ford is the penultimate step of his journey from high security prison to eventual release.

"For me, it's like rehabilitation and finding my feet before I get out. This is an opportunity for me and I wouldn't do anything like that [rioting] because I've just got too much to lose."

Image caption Specialist prison guards in body armour quelled the riot involving around 40 inmates at Ford Open Prison

But not everyone is so willing to stick to the rules, says Mark.

"Shorter term prisoners come here and start to erupt because they have nothing to lose because they know they will be released."

This is echoed by Colin, another prisoner who spoke to 5 live Investigates - he has spent time in a number of open prisons, including Ford.

"I think they need to be a bit more strict with their vetting system, and who they are allowing in to open prisons."

"I can remember many years ago it was difficult to get to a 'Cat D' - an open prison - and now they seem to be doing it to anyone, including violent offenders."

"They get to a Cat D quite easily. It doesn't mean so much to them as it does to the long-termers."

The wrong crowd

Mark Freeman, the Acting General Secretary of the Prison Officers Association (POA), agrees that too many unsuitable convicts are placed in Category D jails, instead of tougher Category A-C prisons.

On the riot night, four of the first six prisoners arrested had failed their risk assessment to be there, and two were about to be re-assessed. Mark Freeman, Prison Officers Association

"People on three to four month sentences spend a week in a Category B jail and then are down in an open prison for the rest of their sentence.

"They're only in proper jails a week - it's not hard to keep your nose clean for a week. These people should not be in open prisons."

Before being transferred to an open prison, inmates are 'risk assessed' but a combination of over-crowding in prisons and a lack of staff to properly monitor inmates is said to be behind an alleged lapse in these assessments.

Mark Freeman of the POA claims "on the riot night, four of the first six prisoners arrested had failed their risk assessment to be there, and two were about to be re-assessed.

"These six were the ones considered to be the main ringleaders."

In a report published last December by the local Independent Monitoring Board - a group of volunteers who carry out checks at Ford - concerns were raised about minimal staffing at the prison.

This warning was sent to the Ministry of Justice just before the riot, but a government spokesman said no minister had seen the report before the disturbance on New Year's Eve.

Inmate Colin says short term prisoners should be kept out of open prisons, as the current situation is not benefiting anyone.

"I think everyone thinks we've got it cushy in open prisons but that's far from the case.

"We've got to earn the right to get ourselves there, and we've got to earn the right to stay there. We've got to behave and observe all the rules.

"I think certain inmates like me, who've been in for many, many years, need to be slowly re-integrated into society and need the facilities offered by open prisons.

"So, I think the prison service needs to concentrate on the long-term offenders getting into open prisons rather than anyone filling the spaces."

When these issues were raised with the Ministry of Justice, a Prison Service spokesperson told the BBC:

"An investigation into the incident at HMP Ford is still ongoing, so it would not be appropriate to comment on specific questions before it is concluded."

You can hear the full report on 5 live Investigates on Sunday, 30 January at 2100 GMT on BBC Radio 5 live.

You can also listen again on the BBC iPlayer or by downloading the 5 live Investigates podcast.