Since Justice Secretary Ken Clarke proposed reforms to the penal system earlier this month, debate has raged over the efficacy of prison as a deterrent to crime.

 

Full Fact has previously probed the issue of prisoner reoffending rates, and our interest was again piqued by a new set of claims made in Mr Clarke’s Mansion House speech last night.

 

 

The Justice Secretary said: “There is not and never has been, in my opinion, any direct correlation between spiralling growth in the prison population and a fall in crime.

 

“Crime fell throughout most of the western world in the 1990s. Crime fell in countries that had and still have far lower rates of imprisonment than ours,” he added.

 

By way of an example, the Justice Secretary claimed that when Canada cut its prison population by 11 per cent during the 1990s the crime rate fell, but when similar measures were taken in Finland, there was little change in criminal activity.

 

“No one can prove cause and effect,” Mr Clarke argued. “The crime rate fell. But was this the consequence of the policies of my successors as Home Secretary or, dare I gently hint, mine as Chancellor of the Exchequer at the beginning of a period of growth and strong employment? We will never know.”

 

Perhaps not, but we thought a closer inspection of the evidence couldn’t hurt.

 

 

Comparing international crime rates is a complicated business. Full Fact enquired after the source of Mr Clarke’s information from the Ministry of Justice, and was told that it couldn’t be released without a Freedom of Information request.

 

However the most commonly used set of comparative figures for international crime rates is the International Crime Victims Survey.

Whilst these do show an overall downward trend between 1988 and 2004 – the years that bookend the survey – the picture appears much more complicated than is perhaps acknowledged by the Justice Secretary.

 

In the 15 developed nations covered by the survey, five actually showed increases in crime in the 1990s. Most worryingly for Mr Clarke’s defence of his policies as Chancellor, the survey shows crime in England and Wales rising during the 1990s.

 

 

Gallup Europe’s Robert Manchin , a co-author of a report on comparative crime rates in the EU, told Full Fact economic growth can only be seen as a single factor in any improvement in crime rates during the 1990s.

 

“In general there has been a downward trend in crime in developed nations up to the start of the recession, but it has by no means been universal, and justice policy has been an important factor in determining any change,” he said.

 

In relation to Canada, Mr Clarke is correct to point to a falling crime rate in the 1990s, with the International Crime Victims Survey showing a peak in 1991 and a steady decline thereafter.

 

However data published by the Organisation for Economic Co-operation and Development (OECD) casts doubt over the extent to which the Ken Clarke can legitimately link this to prison populations.

 

Whilst the prison population in Canada did fall by 11.5 per cent between 1995 and 2001 – from 131 inmates per 100,000 of population to 116 – it actually rose over the course of the 1990s as a whole, from 123 to 126 prisoners per 100,000 heads.

 

Likewise Finland, the other example given by the Justice Secretary, did see a fall in the prison population over the 1990s, from 65 to 50 prisoners per 100,000, but remained at 59 over the period 1995-2001.

 

This is significant, as the International Crime Victims Survey shows Finnish crime rates rising slightly over the same period.

Given this mismatch in the time periods in which these trends emerge, the sort of link between prisoner numbers and crime rates in the two countries highlighted by Mr Clarke is difficult to sustain.

 

 

As Ken Clarke acknowledges in his speech, it is impossible to definitively identify the causal drivers for any trends in crime levels.

 

However whilst a ‘direct correlation’ between prison populations and crime rates may never be proven, there is evidence to make such an argument legitimate.

 

Crime rates have broadly fallen internationally since the beginning of the 1990s, whilst prison populations have risen across the OECD nations. Furthermore, Canada and Finland, cited as exceptions by Mr Clarke to this supposed link both prove to be more complex examples than the Justice Secretary’s account allows for.