MORE than 83, 000 people in our country are in prison. The prison system is a key part of our system of justice. When successful it protects the public in two ways. First, by holding securely those men and women (usually serious or repeat offenders) who have been imprisoned by the courts, and second by operating prison regimes to maximise the chance that a prisoner, once released, will go straight.

I have one prison in my constituency. Aylesbury Young Offenders Institution is home to about 400 young men, almost all aged between 17 and 21. It’s no Borstal but one of only two high-security YOIs in England. To be sent to Aylesbury, you’ve either committed a very serious crime (almost always a violent or sexual offence) or been too disruptive for another prison to cope.

Over the years, I’ve visited the YOI many times and have talked to staff and prisoners. I’ve also been to two other Bucks prisons: the open prison at Springhill and HMP Grendon, a therapeutic prison housing very serious adult sexual and violent criminals.

My first reflection is that all of us should be more aware than we are of the importance and difficulty of the job that prison governors and officers do on our behalf. Some prisoners are hardened criminals and bullies; some are ruthlessly manipulative; others are emotionally weak and easily bullied themselves. Many have a history of drug or alcohol abuse. None of them want to be inside. But for our prison system to be effective it needs to achieve more than just impose order – difficult enough though that is. All but a tiny handful of prisoners will be released one day, when the term set by the judge is up. How do we make it less likely that someone will reoffend after release?

I support long sentences for serious crimes and I think that privileges and comforts in prison should be conditional on good behaviour. But rehabilitation is also important. In the end, it has to be a decision by the individual offender that he (the great majority are men) will accept responsibility for turning his life round. I believe that the character of a prison regime can influence that choice for the good. Education is one key. Too many prisoners enter gaol unable to read or write. If that doesn’t change by their release, chances of getting a job are slim.

Work and training is a second element. In part that’s about acquiring skills that an employer may need but it’s also about keeping (or learning for the first time) the habits of self-discipline that make someone employable. Alongside those practical skills, many prisoners need to develop emotionally and socially. I’ve met young inmates who before being mentored or otherwise supported inside prison were almost completely inarticulate, incapable of expressing themselves other than through anger and aggression or of comprehending the truth that their victim was a human being whom they had harmed.

Many prisoners come from violent, abusive or chaotic homes. A shockingly high proportion spent some or all of their childhood in local authority care. None of this excuses their crimes. But it does explain why locking them up is right and necessary but not sufficient if we want our society to grow safer.