Leaving prison and starting afresh should be a simple matter of deciding to put the past behind you and staying out of trouble.
By Duncan Walker
BBC News Online Magazine
But for many prisoners, particularly the young, things are not that easy, and huge numbers end up re-offending.
Many young prisoners soon return to custody
As many as eight out of 10 under-18s will return to crime within two years of leaving custody, as will three quarters of 15 to 21-year-olds, says crime reduction charity Nacro.
Young men in this group are among the most prolific offenders in the UK, and allowing them to return to crime brings a huge social cost to other people, particularly their victims.
The problem, experts say, is that there are so many obstacles - from poor housing to finding work - that many people simply end up returning to their old ways.
"The group of people coming out of custody are extremely vulnerable and extremely socially excluded and that combination of factors means there's a likelihood of re-offending unless support is provided," says Nacro.
'Super human effort'
For many young people leaving prison simple things like where they are going to sleep pose immediate challenges, says Claire McCarthy, a senior researcher for prisons charity the Howard League for Penal Reform.
Young people in prisons
63% unemployed at time of arrest
Nine out of 10 admit using drugs
One in five don't know where they will live
Young men 18-20 most prolific offenders
74% of young men reconvicted within two years
Peak offending age for men is 18 to 24
Source: Howard League
Other significant problems involve far higher than average incidences of drugs misuse, family breakdown, bereavement and deprivation.
"It can take a super human effort to get through it," says Ms McCarthy.
Last month the Prison Service and schools inspectors Ofsted released two reports looking at 15 to 18-year-olds in custody - Juveniles in Custody and Girls in Prison.
Juveniles in Custody found nine out of 10 young prisoners wanted to stop offending, and they believed finding a job was key to achieving that goal.
Yet eight out of 10 boys had been excluded from school and four out of 10 admitted to a drug problem.
Girls in Prison found the majority of young women interviewed had poor educational histories, but valued the lessons they took in custody. All but a small minority of the girls had exceptionally low levels of self esteem.
"For too many young people, low attainment at school is related to subsequent criminal behaviour," said chief Ofsted inspector David Bell.
Looking for work without the qualifications most young people have is far from easy, and then there's the problem of persuading an employer that you are to be trusted despite your criminal record.
"We work with one young man who has A-levels and is very bright but is having trouble getting in to university because of his criminal record and had to take cash in hand work," says Ms McCarthy.
Both Nacro and the Howard League believe young people leaving prison are far more likely to get on after leaving prison - and therefore much less likely to re-offend - if they get support.
They suggest things like mentoring and help arranging accommodation and organising benefits are crucial - something which they suggest is increasingly being recognised by the authorities, but still not being properly delivered.
"There's a recognition by the Prison Service, the government and people working in the field that this is the biggest issue in criminal justice at the moment," says Ms McCarthy.
"But the delivery is getting worse because of prison overcrowding and even with the best will in the world you can't resettle all the people being churned in and out of prisons every day."
The Howard League is soon to begin a two-year research programme, talking to young men in prison about their experiences, needs and aspirations.
It says that since 1997 children who offend have received much more support from the authorities, but "from age 18 onwards, young people are essentially dumped into the adult penal system without any of the appropriate support or services at a crucial time in their maturation".
A pilot study by Nacro at Portland Young Offenders Institution in Dorset, found support significantly cut rates of re-offending.
Work to build relationships with the young men started in prison and once they were released they were given support by former offenders who had stayed out of trouble and help with day to day practicalities.
Over the course of the three year Outside Project it was found that of those offered help six out of 10 managed to avoid re-offending, compared to just three out of 10 of those who were not given support.
The findings provide a clear indication of what needs to be done, says Nacro. "Without doubt, the cost of intervention is far less than the cost of crimes over time."
The Howard League says the results will be especially significant among young men.
"At present the most prolific of young offenders get access to the minimum of re-inclusion services," said vice-chairman Martin Davis at the launch of its study.
"If we genuinely wish to see a reduction in offending then this neglect and marginalisation must be rectified."