The Big Question: How can we end the crisis in Britain's overcrowded prisons?

Why are we asking this now?

Prison governors in England and Wales yesterday called for an end to all sentences of less than one year in a radical proposal to ease overcrowding. Paul Tidball, the Prison Governors' Association president, warned ministers that cuts and overcrowding could lead to "widespread disorder" within the prisons system. He said: "Prison, the most expensive disposal option for the courts, should be reserved for those of highest risk to communities and citizens."

How bad is the crisis?

The prison population reached a record last month of 84,442, second only to Spain in Europe. The Government's own projections suggest that the prison population could be as high as 95,800 by 2015, a rise of nearly 11,000 in six years. Penal reform groups believe it could grow more rapidly if urgent action isn't taken to halt the increase.

Why should we care about an expanding prison population?

Rehabilitation concerns aside, the prison governors are worried about riots. In his speech yesterday, Mr Tidball, quoted an email from another, unnamed governor, containing a dire prediction about the potential for sustained violence. The email stated: "The potential for prisons to blow is about as heightened as it gets in my view." Earlier this year, the Chief Inspector of Prisons, Dame Anne Owers, said disturbances in jails had been contained so far but identified "real risks" of a loss of control in the future.

What is the cause of the crisis?

It is a complex mix of longer prison sentences, under-resourcing and punitive legislation. But the basic facts are these. Between 1995 and 2009, the prison population in England and Wales grew by 32,500 or 66 per cent. Almost all of this increase took place within two groups of the prison population – those sentenced to immediate custody (78 per cent of the increase) and those recalled to prison for breaking the conditions of their release (16 per cent).

How can under-funding be blamed for over-crowding when we are building more jails?

It was claimed last month that hundreds of convicts who could be released are being held in jails because the Government failed to invest enough in drug treatment and rehabilitation courses. A criminal justice study commissioned by the Liberal Democrats found that more than 1,700 inmates had served longer than their minimum tariffs under the new indeterminate sentence for public protection (IPP), brought in by Labour four years ago. More than a third of the 5,300 people jailed under the IPP scheme have been unable to attend an offending behaviour or drug treatment programme while in custody. Only 60 IPP offenders have ever been released.

Why don't judges stop sending so many people to prison?

Judges are responsible for setting the length of prison sentences which have, on average, doubled over the last 20 years. But the exercise of their discretion is greatly restricted by legislation passed by Parliament. Some judges who would prefer to impose non-custodial sentence have complained that their hands are tied. The senior judiciary has a history of urging ministers to think again about prison sentences. Lord Phillips, the head of the Supreme Court, and Lord Woolf, a former Lord Chief Justice, have long argued the case for greater use of community sentences to help reduce the numbers in prison.

So are politicians to blame?

The welter of new laws creating new offences and breaches that attract prison sentences or recalls to custody has certainly increased the number of routes to custody. Politicians have also put pressure on the judges to impose harsh sentences and then complain when they don't. But it is estimated that re-offending by ex-prisoners costs the tax payer nearly £11 billion per year, but enormous savings and benefits to society could be made by cutting short term prison sentences in favour of robust community sentences.

How do political parties plan to solve the prisons crisis?

Labour and the Conservatives are locked in a political battle to see who can talk toughest on law and order. Both have pledged to build their way out of the problem by creating more and more prison places to meet the growing demand. The Liberal Democrats favour an alternative approach. Yesterday Liberal Democrat Shadow Justice Secretary, David Howarth, called for a presumption against short-term sentences in favour of, "rigorous community penalties and restorative justice".

What do prison reform groups advocate?

Most penal reformers now agree that prison is not the answer to cutting crime. In a radical report published in the summer, the Commission on English Prisons called for the closure of many prisons and a new direction in sentencing. The commission, set up two years ago by the Howard League for Prison Reform, said the emphasis should be on imprisoning offenders locally so that communities had a financial stake in the cost of sentencing. Its report, Do Better Do Less, concluded that prisons have become "warehouses" where people with mental health problems and those with drug and alcohol addictions are "dumped". Roma Hooper, director of Make Justice Work, says: "Our prisons are in a dire state with spending, overcrowding and re-offending at record highs.... It is time for our political class to understand the facts."

Has the trend always been towards an inexorable rise in the prison population?

No. Between 1908 and 1938 the prison population of England and Wales halved from 21,000 to just over 11,000 - the longest, sustained period of decarceration that the world has ever witnessed. It is not obvious how this was achieved but one key factor was the role of a penal reformer called Winston Churchill who had himself been imprisoned and argued against it for some minor offences.

Why not just release some of the least serious offenders?

The Government tried this in 2007 with an early-release scheme when prisons reached bursting point. Since then more than 60,000 inmates have benefited from the early release scheme. But it hasn't stopped the inexorable rise in the prison population. Yesterday the Government confirmed its commitment to prison. "We are clear that prison is the right place for the most serious, violent and persistent offenders, and we will always provide enough prison places for those who should be behind bars," said a Ministry of Justice spokesman. "But it is not always the right answer for less serious offenders, for whom tough community sentences can be more effective in terms of turning them away from crime and therefore giving greater protection to the public than short custodial sentences."

Is building more prisons the best way to tackle crime?

Yes...

* Prison can be a short, sharp shock, and in some cases this could be just what a petty criminal needs

* Prison places must keep up with the number of offenders sentenced by the courts

* Without enough prison cells, dangerous criminals could be released on to our streets

No...

* There is plenty of evidence showing short prison sentences don't reduce re-offending

* Putting a young offender in custody for 12 months costs more than it would to send them to Eton for a year

* Properly funded community sentences are more likely to change an offender's behaviour