Crime is falling in Scotland. And yet most people would assume, in the recent scrum of political hysteria about ever newer and better methods to tackle offending, that the reverse is true. Over the past decade the overall figures, including housebreaking, car theft and assault, have fallen.

In the same period, however, the prison population has soared.

Scotland proportionately has one of the highest prison populations in western Europe, and spends £279m each year locking people up. The question, when crime is decreasing, is why?

Jackie Tombs, professor of criminology at Stirling University, interviewed the judiciary to try to better understand the discrepancy.

Sheriffs expressed exasperation with repeat offenders. Many said they they did not want to lock people up but that there was no viable alternative, and that mixed messages from ministers about being "tough" on crime whilst cutting the prison population did not help.

Sentencing is completely independent of ministers, but Tombs found that the increase in legislation and "tougher" sentences coming out of the Scottish Executive, including prison sentences for those caught carrying knives, had caused more people to go to prison for longer periods.

"The increase in legislation and in laws giving increased sentencing powers to the judiciary has led to greater use of long-term custody," she said. "We have become more punitive and crime has taken on such significance in the popular mind through political discussions and television series such as The Bill that the public climate is no longer conducive to any kind of rational debate. The more people we put in prison, the more likely it is that we will see high re-offending rates.

"It is not that we don't have enough community alternatives to prison but that there needs to be a big shift in resources from prison solutions to community solutions. A lot of the people on short-term sentences should be dealt with in the community, and we need to cap the prison population."

Since devolution, successive justice ministers have called for a reduction in the prison population. As it has grown year on year, each has argued that their hands are tied because sentencing is the domain of the judiciary and judges are independent.

However, ministers can and do introduce new legislation which includes tariffs on sentencing and they can invest in community alternatives. They can also use their position to influence the debate.

In September 2005, when Jack McConnell, the First Minister, called for judges to get tough on bail, prison governors accurately predicted an increase in the remand population. Many of the laws introduced by the executive include greater sentencing powers for the judiciary. The net result is that more people go to prison for longer.

In 1993, there were 5637 people in prison but the figure has risen steadily since then, despite a decrease of about 20,000 crimes. Last year the average population of the country's prisons was estimated at 7111, 5% up on the 2005 figure.

The latest projections indicate that at least 9500 prisoners could be locked up in Scotland's jails by 2015. Such projections do not factor in recent warnings from prison officials that legislation on sentencing, currently going through parliament, would add an additional 1100 prisoners to the total. This would take the figure to 10,600 inmates, the highest pro-rata prison population in Europe.

When Cathy Jamieson took over the justice portfolio in 2003 she pledged to reduce Scotland's burgeoning prison population, tackle inefficiency in the courts and reduce the rates of reoffending. It was an ambitious plan. Stage one involved tackling the courts system. Although recorded crime is falling, advances in police detection means officers are sending more cases through to procurators fiscal and in turn to the courts, which were creaking under the increasing burden of cases.

In 2001, only around 14% of high court cases actually went to trial at the sitting to which they were first indicted. Changes introduced by the executive following a review of the high courts by Lord Bonomy have brought a 90% drop in trial delays, meaning far less heartache and inconvenience for victims and witnesses.

Ministers also introduced and extended specialist courts to tackle drugs, domestic abuse and youth crime. The drug court in Glasgow has been so successful it is now being copied by England and Norway.

Drug Treatment and Testing Orders (DTTOs), one of the measures administered in the court, are available across Scotland as an alternative to custody, but the drug courts themselves have not yet been rolled out, a decision thought to be motivated by their cost.

The two pilot schemes have already cost more then £6m. But with more than 80% of new prisoners testing positive for drugs, and up to 40% of those in prison still testing positive, thousands of people are thought to be eligible for DTTOs.

The evaluation of the courts also revealed that orders are more cost-effective and more likely to change long-term behaviour than prison. An 18-month order at the Glasgow drug court costs £24,408, almost half the cost of the same period in prison, which is £46,008. Research shows that every pound spent on drug treatment saves £3 in the criminal justice system.

Why, then, are we still locking up so many chaotic drug users when the cause of their offending lies predominantly in their addiction?

Of the prisoners released in 1999, 60% were convicted of another offence within two years. In contrast, 42% of offenders who received a community service order were reconvicted.

Since 2004, further use has been made of community sentences but experts say this had little impact on prisoner numbers because of a lack of resources. The executive also introduced Supervised Attendance Orders as an alternative to custody for low-level fine defaulters.

Yet in spite of this, 6098 people were imprisoned in 2004-05 for defaulting on fines. More than 85% of them had failed to pay fines of less than £500. In one case, a woman was jailed for failing to pay the final £10. Even the chief executive of the prison service, a branch of the executive, called for legislation to stop the practice altogether.

Roger Houchin, at Glasgow Caledonian University, found that people living in Scotland's poorest areas are now more likely to be imprisoned than black men in the US.

He revealed that half of the jail population is drawn from a tiny section of society - just 155 of the 1222 council wards - and that in the most deprived parts of Glasgow, one in nine people will have been jailed by the time they are 23.

Few would argue that violent prisoners should be released to ease the strain on cells, but reports from the chief inspector of prisons say that there are far too many people locked up who should not be there at all and whose behaviour could be addressed more effectively in the community.

Successive reports highlight the need to tackle the root causes of crime: poverty, poor education, unemployment and low aspirations. However, this appears to be the least alluring political option.

A case in point COLIN Munro was 15 years old when he was hit by a car while cycling home on a quiet country road in Fife. The schoolboy, who was a meticulous cyclist, was killed instantly.

The driver, who was described as "blind drunk", was sentenced to eight years in prison for culpable homicide, but four years later Colin's parents, Ann and Ronald, were informed he was due to be released.

They were understandably angry and upset, but decided that speaking to him and hearing his apology would help them come to terms with what had happened to Colin.

The meeting was one of the country's first organised by Sacro's Talk After Serious Crime scheme, a restorative justice scheme for the victims of violent crime. This type of meeting has been endorsed by the Scottish Executive.

"The driver himself was never allowed to speak in court and by denying him the privilege of speaking they denied us the privilege of hearing him apologise," said Ann Munro, Colin's mother.

"Lots of people questioned whether it was really wise but it was worth it because we got the apology we desired and he got the peace of mind of having made that apology." What the parties say Labour Officials failed to respond to requests to provide detailed policies. However, Labour is expected to introduce US-style community courts. Restorative justice - allowing offenders to make amends with victims - has been highlighted in the context young offending.

Preventing violent crime through early intervention is a priority. SNP Relieve the pressure on our prisons with tougher new community punishments to end what is often a revolving door of short custodial sentences. This will free prison officers to deal with the serious offenders and maximise the impact of prison-based schemes to reduce re-offending. Conservative Stronger sentencing policies are needed which would require at least a third extra prison. Anyone handed a third custodial sentence would receive an additional tariff automatically. Convicted criminals will spend their entire sentence in prison. Mandatory drug treatment and testing order for all prisoners. Lib Dem Introduce tough community sentences, making criminals work to repay their crimes and stop them from re-offending. The Lib Dems also believe that we should radically shift the focus on to tackling re-offending by replacing the Prison Service with a Custody and Rehabilitation service. Greens Genuine rehabilitation is crucial, together with more use of community sentencing (without compromising public safety) and victim-offender mediation to cut re-offending. Prisons need time and space to tackle offending behaviour and drug addiction. There should be far better support for the children of prisoners. SSP Expand prison rehabilitation programmes, including education, training, psychiatric support, drug and alcohol detox, rehab and abstinence programmes. Reverse all privatisation and PFIs in the prison service. Create a new fast-track appeals system to deal with suspected miscarriages of justice. Solidarity Introduce an Offenders' Rehabilitation and Restorative Justice Bill to the next Parliament. Prisons should be for the leaders of organised crime, dangerous, violent criminals and sex offenders only. The vast amounts of money spent on keeping people in jail is better spent on efforts to change offending behaviour and attitudes.