Max Chambers is Head of Crime and Justice at Policy Exchange, which is about to embark on a wide-ranging study of future crime threats, assessing government’s preparedness for tackling them and the capabilities of law enforcement that will be required. Please email for more details of how to contribute to the study.

Was it, as infamously suggested in Steven Levitt’s book Freakonomics, because legalised abortion reduced the number of unwanted children? What about the fall in the amount of lead pollution, meaning children’s brains were not so damaged by their environment? Or is it simply, as Steven Pinker argues in his terrific book, The Better Angels of our Nature, that our increasingly connected and interdependent species is just becoming more and more civilised as the centuries pass?

There’s little doubt that the stories we tell ourselves about why crime has fallen so dramatically are becoming ever more eclectic. The truth is that no-one – including the world’s leading criminologists and social scientists – can say conclusively what the decisive factors have been in the steep decline the West has experienced in the last twenty years.

Of course it’s likely that better parenting, economic growth, low unemployment and an ageing society all had some impact – and newer theories about pollution and the internet are interesting, too. But what’s common about all of these different hypotheses is that any impact on crime rates they caused was essentially accidental – a mere by-product of an economic trend, a demographic change, or a social policy in which crime reduction was rarely a consideration, and certainly not a conscious goal.

All of this begs the question: have government crime policies actually made any real difference to crime? Here, there is good news. One clear example of positive government action was the advent of a more proactive policing style, with greater use of stop-and-search and more targeted enforcement activity, the introduction of which in the United States and the UK correlates strongly with the great crime decline. Policymakers would do well to remember this as they tweak with stop-and-search, though there are certainly big improvements to police practice that can be made.

However, there is perhaps an even more instructive example of a strategic government intervention which made a massive, disproportionate impact on crime.

In the 1980s and 1990s, car crime in the UK was rampant. In 1995, almost 600,000 vehicles were stolen – an epidemic by any yardstick. But by 2003, car thefts had halved to just 300,000. And last year, just 80,000 vehicles were stolen, a staggering reduction of 87 per cent. In one sense, the reasons for this dramatic development are obvious: the widespread introduction of new measures like immobilisers, steering locks, car alarms, central locking and electric windows transformed the security of vehicles, making cars much harder to steal or break into. Iin-built computers have replaced car radios (which were easily stolen) and GPS tracking makes stealing a vehicle much more risky for the perpetrator.

What is sometimes forgotten is the crucial role that the government played in catalysing these developments. In the mid-1980s, as car theft began to rocket, ministers and a team of researchers at the Home Office began to take a real interest in car crime. A 1985 Home Office report contended that car security could be transformed through modern technology and the standardisation of best practice, with minimal interference to the design of cars and at relatively little cost. But the report was largely ignored by industry and the problem – best exemplified by the fact that the Ford Cortina could be unlocked with any Ford Cortina key – continued to grow.

So ministers got tougher, with high-profile crime prevention seminars and summits held at Downing Street, aimed squarely at compelling industry to take action. As well as political pressure, the Home Office eventually developed a new tool – the Car Theft Index – which served to ‘weaponise’ their efforts.

A simple but brilliant concept, the index used crime data to rank each car – every make and model available – according to how regularly they were stolen, compared to their market share. The results of the first index were astonishing. In 1992, the major manufacturers were invited into the Home Office to be presented with the results, and a deluge of press and TV attention put the issue of manufacturers’ responsibility front and centre in the debate.

The Car Theft Index changed everything. Security quickly became central to the marketing of cars and manufacturers began to incorporate much more sophisticated security measures into the design of all cars. The scale and breadth of industry response meant that costs were kept to a minimum and no competitive advantage was lost. As older cars were gradually replaced with new ones, more secure, ‘target-hardened’ cars now came to dominate the vehicle fleet. And it didn’t just change the car market in the UK, it led to changes right around the world.

The lessons for policymakers are critical, but too often ignored. Even with less money to go around and policing cuts making the thin blue line thinner still, government can do still do things that dramatically cut crime. The challenge is twofold: first, which industries are in similar positions in 2014 to the car industry of the 1980s? Which companies do not give sufficient attention to the security of their products, or how they can be used in the commission of crime? Who, by omission, is not fulfilling their social responsibilities to consumers and wider society?

That’s the easy bit. Just consider how the web is providing new global markets for stolen goods, how illegal drugs can be ordered online and delivered to your door, how child pornography, counterfeit goods and dangerous weapons are available in just a few clicks. Think about smartphones and tablets, containing so much vital personal data, but so easily stolen, ‘cracked’ and resold by thieves. Consider virus protection – not mandatory, not standardised and updated at the discretion of the consumer. Think about the insecurity of contactless bank cards, or the number of us who have had money stolen from our bank accounts. Or take the alcohol industry: does anyone believe that drinks producers are designing, targeting and promoting their products with crime reduction as a primary concern?

Rather than waiting until online fraud (up 27 per cent last year alone), identity theft or smartphone robbery reach epidemic proportions, the second part of the challenge is to get ahead of the curve and deal with future crime threats. How can government act now to change business behaviour, encourage industry-led solutions and prevent these products and technologies becoming the big growth areas for crime in the next decade? Is competition, naming and shaming, and political pressure going to be enough, or will regulation and legislation be required? What are the trade-offs between liberty and security that will need to be considered as we deal with the consequences of the proliferation of social media and big data?

The Car Theft Index suggests that there should be no counsel of despair for crime policymakers. Government can do small things, clever things and inexpensive things that would have a huge impact –not through expensive social programmes to persuade habitual offenders to give up their criminal careers, but simply by curbing the opportunities for crime in the first place. That’s the best way of cutting volume crime and keeping a lid on emerging threats.  That’s what we mean when we say government should be smart on crime. It is, quite simply, the best way to ensure that it keeps going down.