By Stephen Robb BBC News Online

The Prison Reform Trust says inmates left alone are vulnerable

Mark, 34, of north London, has been jailed four times in eight years for offences including robbery, theft and causing actual bodily harm.

His longest term was two years, and his most recent 10-month spell was completed in April of this year.

Though he was never driven to harm himself while at Her Majesty's pleasure, he said there were numerous attempted and successful suicides by fellow inmates.

Vulnerable

He agrees with Prison Reform Trust claims that offenders entering prison with drug or mental health problems are particularly vulnerable.

It sometimes can be hard to keep a grip on your own values... people come in without drug habits and leave with them Prison suicides hit record high

"People do come in with serious problems that are not addressed, and it is those things that can drive people to do desperate things."

Mark also argues that imprisoning minor offenders alongside "hardened criminals" can have a damaging effect.

"What you are getting is more and more people in there for less and less serious offences. They may or may not be career criminals, but they find themselves rubbing shoulders with people who are career criminals. The mentalities are totally different. It is scary."

If nothing else, minor offenders can be led further astray, he said.

"It sometimes can be hard to keep a grip on your own values. They will share their criminal attitudes, and it may be you start to think like them.

"You want to be one of the group - it is not good to feel isolated in a place like prison."

For example, "people come in without drug habits and leave with them", Mark said.

Adjustment

"For someone who is fresh into prison, depending on their character, dealing with the adjustment could be something that is hard to do.

"You have lost your home, you have lost your family, maybe you have lost your job. There is no way to prepare you for being in prison.

People are not listening to you and they are not hearing what you are saying - frustration builds up

"When you are faced with the bars and the inmates and the smells and the noises, it is daunting."

Tiny cells that force prisoners to go to the toilet where they also sleep and eat meals are "degrading", Mark added.

Events outside the prison that are "beyond your control" can also have a dramatic effect on inmates' state of mind, he said.

"My dad died when I was in there. I was fortunate enough to get bail to bury him, but so many others don't. Those kinds of things people have to deal with."

Frustration

Mark said that prisoners who repeatedly tried to harm themselves would often be put on suicide watch for a short time then returned to their old cells, only for the cycle to continue.

"I had people in my cells who were self-harmers. The best thing I could do was talk to them, get them to explain what that was all about.

Much of the time we are treated like numbers, but we are not just numbers

"If someone in prison decides to try and kill themselves, I don't know how you remedy that. There needs to be some kind off communication."

While prison life drives many inmates to hurt themselves, many more attempt to harm other prisoners or officers, he said.

During a spell at London's Pentonville Prison, Mark said that he witnessed fights on a daily basis.

"I can understand why people will sometimes kick off and fight. Inmates are not getting things that they require. People are not listening to you and they are not hearing what you are saying. Frustration builds up and people take it out on others."

Mark, who is due to start a university degree this autumn, suggested that it was the dehumanising effect of prisons that did the greatest damage.

"Each individual needs to be assessed on a case by case basis, trying to find where that person is at on a personal level.

"Much of the time we are treated like numbers, but we are not just numbers.

"We are people and we have feelings and thoughts, we hurt and we have emotions, the problem with prison is that it is not set up to deal with things like that."