Prisoner numbers have reached a record high in England and Wales. Calls have been made for prison sentences of less than a year to be abolished "because they do not work".
What is the current prison population?
There are over 84,000 people in custody, despite around 2,500 inmates being released more than two weeks early from their sentences every month.
The Ministry of Justice
by 2015, there will be 93,900 people incarcerated.
The current prison capacity stands at 85,404.
The Prison Reform Trust said almost
two-thirds of prisons
were officially overcrowded, and the system holds 10,000 more offenders than it was designed to handle.
Why do numbers keep rising?
The 2003 Criminal Justice Act, which overhauled sentencing policy with the aim of making it clearer and more flexible, emphasised reserving custody for dangerous, persistent and serious criminals and making greater use of community orders for low-level offenders.
With a new focus on making punishments fit the crime, it was hoped that the Act would help stabilise the prison population.
It has introduced a new type of indefinite sentences without a fixed final release date for sexual and violent offenders considered a danger to the public.
This means they are effectively kept in jail until the Parole Board deems it safe to release them and this has led to a rise in longer prison terms.
Critics say the overall effect has been one of sentence inflation.
What other factors are there?
A steep rise in the number of criminal offences since Labour came to power in 1997 has compounded the problem.
Lord Phillips, formerly the UK's most senior judge, criticised the government for introducing a
"ceaseless torrent of legislation",
claiming new laws had increased the burden on the courts system.
It has also been claimed that the government's tough rhetoric on law and order has spurred judges and magistrates to impose more stringent punishments.
And more offenders are being returned to jail under tighter arrangements for breaches of licence conditions.
What changes have been suggested?
commissioned by the Howard League for Penal Reform said prison and probation funding could be diverted to tackling the causes of crime.
The Prison Governors' Association (PGA) is proposing a motion which says prison sentences of less than a year should be abolished because they do not work.
How is the government tackling the problem?
Nearly 25,000 prison spaces have been provided since 1997 - 4,970 of which were built in the last two years. They include new jails and ready-to-use units in existing prisons.
The government is committed to increasing the net capacity to 96,000 by 2014.
The 2008 Criminal Justice and Immigration Act aims at making sure the right offenders end up in custody.
Under the act, non-violent and non-sexual offenders will be automatically freed after half their sentences, instead of waiting until the two-thirds point.
The act was preceded by an emergency measure in 2006 which saw early release for some offenders after prisons reached full capacity.
When the measure was introduced, it garnered unwelcomed headlines when a small number of those released early committed eight more crimes after being let out.
Since June 2007, 52,117 prisoners have been let out up to 18 days before the halfway point of their sentence.
What is Operation Safeguard?
The government reached an agreement with police in October 2006 to use 400 of the estimated 900 cells at stations in England and Wales as emergency prison accommodation.
Although the operation is on-going, the last time a prisoner was held in this way was September 2008.
Are there other options?
Increased use could be made of electronic tagging which allows low-risk offenders to serve part of their sentences at home.
Plans to ensure jail numbers are taken into account when sentencing have apparently been shelved, while calls for mentally ill prisoners and vulnerable women to be released from jail have been stymied by a lack of suitable alternative accommodation.
What about foreign nationals?
The rise in the number of foreign nationals in UK jails has been attributed to tougher sentencing and a clamp down on drug trafficking.
The government wants to speed up their removal, but deportations take a long time.
A cash incentive introduced in 2006 to encourage prisoners from overseas to return home, has been judged a success after a self-imposed target of removing at least 5,000 convicted foreign criminals was met.
Among the deported foreign prisoners were 50 people convicted of killings or attempted killings, 200 sex offenders and more than 1,500 people found guilty of drug offences.