Friday marks a winding down of the controversial prisoner early release scheme. Drawn up to ease pressure on overcrowded jails, the scheme says much about changing attitudes to law and order.
If you want to know what happens to criminals - look at the graph above. And it's the sudden sharp upward line during the 1990s that explains one of the major challenges for the current government - and whoever walks into the Ministry of Justice after the general election.
Friday marks the beginning of the end of one of the most controversial law and order policies of the moment - the so-called prisoner early release scheme.
The End of Custody Licence scheme - to give it its official title - was an emergency measure introduced in summer 2007 as the prison population hit 81,000. Prison governors were putting up the penal equivalent of "no vacancies" signs as bosses back in London frantically rang around looking for spare cells.
At the heart of the crisis was a slow-burning fuse lit by fundamental changes in how prison is used in England and Wales.
For the first half of the 20th Century, the prison population hovered up and down around the twenty-thousands.
The figure steadily rose during the second half of the century - before surging after 1995.
Do we have more prisoners because there is more crime? No - the two key measures relied on by government show that overall crime has been generally falling or remains statistically stable.
A rising prison population can, in part, be explained by the overall growing population. But the real reason for the hike is the UK is jailing more people for longer, a trend that began under John Major's Conservative government and has continued under Labour's Tony Blair and Gordon Brown.
So while 20 years ago a repeat petty offender with a drug problem might think he'd walk out of court with a probation order, today his solicitor is more likely to tell him to prepare for prison.
A second factor has been the introduction in 2005 of special indeterminate sentences, for public protection - or IPPs. So while a violent offender could be given a minimum three-year term for a crime - under the scheme, he could be held far longer if it's felt he still poses a danger to the public. Q&A: Indeterminate sentences
There are now almost 6,000 IPP inmates. More than a third have completed the minimum term set out by the judge. But only about 75 have actually been released.
Who got released?
About 80,000 prisoners have benefitted from the End of Custody Licence scheme. It allows someone to be released up to 18 days before the halfway point of their sentence.
Criminals were eligible if they were sentenced for between four weeks and four years for a range of less serious offences and had not broken a number of rules.
As the graphic shows, these are offences at the lower end of the scale. But here's the bitter pill for ministers. These are the kinds of offences that are the most common in society - and therefore the kinds of things that people will have most personal experience of. And that's why Lord Woolf, the former Lord Chief Justice, last year joined the chorus of voices saying that the scheme was eroding public confidence.
The number of criminals who have committed new crimes while out on ECL has been relatively small - about 2,500, or 3% of all those in the scheme. A further 1,574 offences were committed by offenders who had been released under the scheme.
Among those was Andrew Mournian who murdered his girlfriend Amanda Murphy in 2007, five days after being released.
Did the ECL achieve anything?
The ECL has been politically difficult - but it bought the government time to get new prison cells open.
The prison population hasn't fallen - it has continued to rise and is now at a near-record 84,000.
That's 2,000 higher than at the same time last year - but crucially 2,000 lower than what the Prison Service calls its usable operational capacity, thanks to the opening of new cells.
But as this graphic shows, prisons are still overcrowded, based on their own official numbers.
So what will happen next? Justice Secretary Jack Straw has told Parliament that ending ECL will absorb 1,000 of the spare places.
The plan is to have 96,000 places by 2014 thanks to a prison building plan.
But the Ministry of Justice's own projections - that's technical language for a best guess - is that the population could hit 93,900 in the summer of 2015, which shows how tight things might still be.
Which projection is the most accurate? That will come down to the new Sentencing Council which starts work next month.
It is tasked with promoting consistency in jail terms by monitoring how judges are dealing with cases and issuing more specific guidance.
But the Council of Circuit Judges has warned that the new rules may lead to more people being jailed as the 600 judges it represents lose more of their discretion in individual cases.