A long-term fall in the number of heroin and crack users has been a key factor in the decline in crime levels in England and Wales, according to Home Office research.

A consensus among criminologists over a convincing explanation for the rise in crime to a peak in 1995 and its subsequent long-term decline by more than 60% in England and Wales has long proved elusive.

But Home Office researchers say they may now have established that the heroin epidemic of the 1980s and 1990s was one important driver of those crime trends.

They say focusing on reducing the remaining number of heroin users could produce further significant reductions in crime levels, even if the levels of other illicit drugs – such as cannabis, legal highs, powder cocaine and ecstasy – remain much higher.

The author of the research, Nick Morgan, is careful to say it does not prove that this link is the only explanation for the fall in crime over the past 20 years, but says it is an important driver.

His study suggests that at least 50% of the rapid rise in "acquisitive crime" – high-volume burglary and car theft-type offences – between 1981 and 1995 can be attributed to a rapid rise in the number of heroin users. It also suggests that a decline in the number of heroin users can be linked to between 25% and 33% of the substantial fall in acquisitive crime since 1995.

The research assumes that acquisitive crime makes up about 60% of total crime levels, which would also include violent crime and other offences.

Morgan says the evidence shows that heroin and crack users commit markedly more crime than offenders not taking these drugs, and that the number of users increased dramatically in England and Wales – and many other western nations – in the 1980s and 1990s and then tailed off as users quit or died.

The study assumes that heroin users tend to commit the larger-volume minor theft or drug-dealing offences rather than the violent and sexual crimes that cause the most harm.

"These two – largely undisputed – facts offer a compelling explanation for at least some of the rise and fall in crime, which has received relatively little attention, especially in relation to the decline in crime," says Morgan.

"At the national level, England and Wales, the US, the Republic of Ireland and many eastern European nations had peaks in acquisitive crime that matched the timing of their heroin epidemics, rather than each other. The same is true for regional exceptions like Merseyside and Edinburgh," he adds.

Morgan says that while there are areas that did not follow this pattern, such as the West Midlands, the analysis "surely offers the best chance of unlocking the crime -drop puzzle".

The research paper considers other common explanations such as the changing nature of the economy, greater car and house security, changing demographics among young offenders, imprisonment rates and even the removal of lead from petrol, and says that "despite much imaginative scholarship" a convincing overall explanation has remained elusive.

"Many factors are likely to have been important and interactions may also be crucial. Indeed, some findings suggest that rapid rises in unemployment at a time when heroin use was spreading may have exacerbated the crime impact beyond the level that either factor would have had on its own," Morgan concludes.