The first suggested that the rise in crime over the past 20 years is far more closely connected with the rise in mass unemployment than even left-wing commentators had previously believed. The work of David Dickinson, an economist writing for the Labour- leaning Institute for Public Policy Research, it examined long-term trends in great detail and, among many other things, demonstrated the simple fact that most criminals are unemployed.
The second study, by Gwyneth Boswell of the University of East Anglia, reported on the backgrounds of children who kill, rape and injure. Again the picture was grim. After looking at 250 juveniles in prison or in care for the most serious crimes, Dr Boswell found that 40 per cent had been beaten and bullied before they turned to crime and another third had been raped, buggered or otherwise sexually assaulted by a relative or family friend.
The third study was the massive Psychosocial Disorders in Young People, edited by Sir Michael Rutter of the Institute of Psychiatry at London University and Professor David Smith of Edinburgh University. Their findings were radically different. Forget about poverty and sexual abuse, they seemed to say, the real cause of social and psychological disorder was post-war freedom and individualism.
The responses to these three studies provide a good gauge of the state of the cultural war over where the blame lies for what is going wrong with Britain. Not one national newspaper reported on David Dickinson's findings. Dr Boswell was a little luckier: three national newspapers carried modest articles on her study. The Rutter-Smith report, however, was shouted from the rooftops.
"Permissive Sixties are to blame for the teenage troubles of the Nineties," proclaimed the Daily Mail. "A pioneering international study explodes the myth that youngsters can blame anti-social behaviour on unemployment, poor housing or broken homes." Crime was caused by "confused young people, growing up in a moral vacuum [who] cannot cope with the sexual freedom and licentiousness which were the watchwords of that decade."
The Daily Telegraph announced: "Rising tide of crime is blamed on sex, drugs and rock 'n' roll," and added an editorial admonishing deluded liberals for thinking that poverty had anything to do with it. "Children today grow up far too quickly," sighed a Guardian columnist after reading the report. "They no longer communicate but sit with their Walkmans on in front of the TV lost in the alien world of youth culture."
Sir Michael and Professor Smith are embarrassed by the coverage. They are academics, after all, and their findings are more tentative than the reports suggested, peppered with all the usual scholarly conditionals and calls for every observation to be submitted to further research for confirmation. Their underlying message, however, was not distorted.
"Psychosocial disorders", they said, may be caused by better schooling, which raises expectations that are difficult to fulfil. There was no direct connection with poverty. Parents who divorced added to the pressure, while the growth of youth culture and of youth markets for music and fashion isolated the young from the beneficial influence of adults and introduced them to sex and the heartache of broken relationships far earlier than previous generations.
"The belief that people should be free to choose their own way of life and be able to satisfy their own desires," said Professor Smith, "could be connected to the growth in crime and suicide."
It should come as no surprise that, of the three studies, it was the Rutter-Smith report that received all the attention. It was the one that challenged an idea that seems both natural and sensible to most of us: that need causes crime as well as greed. When people find that they are unable to afford necessities, or luxuries that they can see others enjoying, they are more likely to be tempted to steal.
If a study by reputable experts suggests this is wrong, then it is news - more so than a study that merely confirms something we believe we know, however depressing that knowledge may be.
But there is a heavy political weighting to this as well. Rejecting the idea that crime could have social causes has become a staple of modern Tory thought. When the Conservatives came to power unemployment was under a million and the police recorded 2.5 million crimes. In 1993, nearly 3 million were unemployed and 5.5 million crimes were recorded. When unemployment fell in 1987 and 1988, so did crime. When unemployment rose in 1990 and 1991, crime followed suit.
Margaret Thatcher and her successors in government have always denied that there is any link. "We should have no truck with trendy theories which try to explain away crime by blaming social-economic factors," Michael Howard, the Home Secretary, told an audience of Basingstoke Conservatives in 1993. "Criminals ... should be held to account for their actions. Trying to pass the buck is counterproductive and dangerous."
Right-wing newspapers that share this view understandably greeted the Rutter-Smith report with jubilation.
But the ecstatic coverage ignored the odd implications of the academics' findings. Education leads to expectations which cannot be met, they say ... what are we meant to do? Close schools? Youth culture and youth sex leads to crime and suicide ... should we ban both?
There may be a grain of truth in their criticism of people who look only at poverty when they discuss crime but at least men such as Mr Dickinson, whose report was so neglected, appear to offer practical solutions. Tackling unemployment may be difficult, but it would be child's play in comparison to changing the attitudes of every teenager in Britain.
To show that connections between criminality and joblessness have existed for decades, he looked at who actually commits crimes. A 1972 study of 18-year-olds in London showed that the offending rate was three times higher for the unemployed. Research by the Northumbrian police between 1975 and 1980 showed that about one-third of all offenders were unemployed men. In 1993, the National Association of Probation Officers surveyed 1,331 convicted offenders and found that 79 per cent were living on means- tested benefits.
Moving from the small to the large scale, he then looked at young men, the group most likely to be involved in crime and showed that their rate of offending was closely correlated to rises and falls in the unemployment rate. The fit could be tightly measured: every time the jobless figures went up by 1 per cent, there was a 0.4 per cent rise in burglaries.
This is not a particularly radical idea. A report from within the Home Office itself, which was leaked last April, concluded that all the evidence from Britain and abroad showed that the "single most effective form of intervention was the provision of employment to offenders".
Against this background, the Rutter-Smith findings look exposed. Paul Cavadino, chairman of the Penal Affairs Consortium, which represents civil liberties pressure groups and workers in the criminal justice system, finds very little about it to agree with.
"No one suggests that mass unemployment is the sole cause of crime, but to deny it is prominent among the reasons is absurd," he said. "The correlation between high unemployment and high crime is so obvious to most people that commentators have been forced to work hard to find more and more bizarre explanations to deny it."
Bizarre or not, three such explanations have emerged. The first is that crime and often poverty are not social and economic problems but have a genetic cause, predisposing some people towards aggression. The second is that there can be no inevitable link between unemployment and crime because in the 1930s millions were out of work but the country was peaceful. And the third is that a country's morals determine whether it is a happy and safe place to live.
Sir Michael Rutter and Professor Smith are associated with all three of these arguments. Let us look at them in turn.
First, the genetics. Earlier this year Sir Michael chaired one of the most controversial scientific conferences in recent memory. Selected speakers were invited to discuss "criminal genes" behind closed doors. At a press conference two American scientists suggested that abortion should be considered when testing indicated that a child was likely to be born with genes which allegedly predisposed it to aggressive or anti- social behaviour.
While not necessarily endorsing the call for a genes police, Sir Michael added that genetics could lead to a better "understanding of how risk factors operate, which is important for intervention and prevention".
Britain's leading geneticists reacted to the conference with anger. The whole attempt to unravel human behaviour - the result of a complex interaction between genetic predispositions and the environment in which people are brought up - and find a gene for aggression was dangerously misconceived, they said; it was like trying to unbake a cake and fit the ingredients back in their packets.
Steve Rose, professor of biology at the Open University, derided the assumptions behind the conference and noted that middle-class genetic determinists worried only about the crimes of the poor and never asked whether managers, say, had a gene for fraud.
"Violence in British society has risen dramatically over the past decade," he said. "In the US the homicide rate among young males has doubled since 1985. There is no conceivable genetic explanation - this isn't a mutant gene suddenly appearing."
An open letter signed by 15 scientists said it was "alarming" that the conference did not include "speakers with a viewpoint critical of genetic determinism. It gives the impression that genetic causes of crime are more important than social causes."
What about the 1930s? It is very difficult to compare the 1930s with the 1990s, because the way the police record crime has changed beyond recognition. But although there were undoubtedly far fewer crimes 60 years ago, the crash of 1929 still had profound affects on law and order.
The number of men found guilty of indictable offences rose by a third between 1929 and 1932 and crime rose fastest in the "depressed areas" of the North. In 1931, the Prison Commissioners for Nottingham Jail looked at their young inmates and wrote that half of them had a "difficult or even hopeless" future. "Less than 50 per cent have jobs to go to or even unemployment benefit to draw and it is difficult for them not to return to prison." The next year Sir Herbert Samuel, the Liberal politician, drew the attention of the Commons to the fact that the graph of crime was, year after year, following the unemployment graph.
The argument about historical contrasts does not end here. It is suggested that, for whatever reason, modern youth suffers more "psychosocial" stresses and depressions than their predecessors. Crime comparisons across the decades may be hard to make, but the troubles they bring are minute in comparison with the task of working out the relationships between the states of mind of people today and in the past.
But Sir Michael and Professor Smith assert that the evidence from across Europe shows that young people born before the Second World War had far fewer "psychosocial" problems than young people born afterwards. This approach can have peculiar consequences. In the case of Germany, from where last week's study drew data on mental disorders of different generations, it raised the prospect that we should think of the generation which, on the whole, supported Hitler and waged war across Europe as well-adjusted, while regarding the post-war generations who built the modern German democracy as deeply disturbed.
It may be tempting to dismiss Sir Michael and Professor Smith as ideologically- driven reactionaries, but that would be unfair. Their 800-page study is rigorous, detailed and cautious. The professor said last week that he regarded the imputation that he was a conservative as completely wrong. "In the past 15 to 20 years high unemployment and growth in inequality has led to crime," he said. "My biggest worry is the existence of a group of young people permanently disenfranchised who don't participate as citizens. We've yet to see the full consequences of the creation of this class, but I fear them."
He added, however, that you could not get away from the fact that crime started to rise in the "golden era" of low unemployment and high living standards which began after the war and ended in the oil crisis of 1973. So, too, did the growths in drug-taking, alcoholism and suicide.
This brings us to the third non-economic explanation for social breakdown -changes in morals. Here the ideological battle-lines begin to blur. The real 20th-century revolution in most Western countries is the collapse in traditional family structures and the ending of sexual and social taboos. Few believe that increased freedom has not brought some unhappy consequences.
Robert Reiner, professor of criminology at the London School of Economics, who has argued with Professor Smith in the past, says that culturally repressive societies had the advantage that citizens did not need to be coerced into behaving themselves. They had "a policeman in their heads" which kept them out of trouble.
That policeman seems to have gone, but we are not about to set aside our personal freedoms to bring him back. The question is, can we restore a more morally responsible culture without loss of civil liberty? Professor Smith is optimistic. There is nothing inevitable about bad parenting, he said, and couples can be taught and encouraged to spend more time with their children.
Professor Reiner disagrees. Permissiveness by itself does not bring crime, he insists. Sweden and the other Scandinavian countries are very permissive, but law and order is not a great problem there because the market is strictly controlled by Keynesian policies and social democratic intervention. In other words, its cultural climate is permissive, but its economic climate is more controlled.
"The difficulty for Britain is that we have the worst of both worlds," he says. "We have the free economic market and permissiveness at the same time - economic and moral laissez-faire, if you like. There's no point in telling the young to be responsible if you won't intervene on social democratic lines and offer them the reward of a job or a place in society. You can try to preach, but they won't listen."