Why is a prisoner released after serving half his sentence?

The system of early release was introduced as a way of encouraging prisoners to behave whilst inside.

If they had nothing to look forward to other than their full sentence, many caused riots and disruption.

'If you behave, we'll let you out sooner' has become the norm.

It's not just in the UK, it happens in virtually all western countries.

North African and Asian countries don't seem to operate the same way, it's very much a case of 'You've got 'life' so that means, 'till you die'.

In the UK, life is generally about the 21 year term, which is why a judge will sometimes specify, 30 years, or however many he thinks will keep that person in prison for, literally, the rest of their lives.

Two different reasons, The time spent in jail waiting for trial is included which may be more than a year.

Around midway in the sentence is when parole comes up and if you are on good behaviour and the patrol board think you are reformed...

because the existing jails cannot accommodate them for the full length of their sentence, so to avoid building more prisons, prisoners are released after serving half their sentence, subject to for-filing certain conditions.

assuming they are of good conduct, in the last year of custody they are sent to a low category prison/open prison, where they are aloud out on working parties and can for example have a mobile phone, (which cannot be taken into the jail) every month they get 5 days home leave to establish themselves back into their home town, and acquaint themselves with a designated probation officer, (as after their release they will be on probation for the rest of their sentence)

any infringement of the prison rules results in the immediate transfer to a high category prison to serve out the rest of their sentence, where they are locked up for 18 to 20 hours a day, with no home leave.

there are obvious exceptions to this where violent prisoners pose a threat to society, and they are retained in custody.

as most career criminals have no problem with compiling with low category prison rules, as they don't like the alternative for offending, it seems a good basis to deploy similar constraints against rebellious children who feel they are above the law.

Not just England, USA too and for all I know most of the civilised world.

Its a WAY

To make them behave better in the messed up system

Better they are earlier they released

It's probably because our prison's are "Over crowded" me think's