Although the exact proportion of crime that is committed by users is not known, research shows that drug use is not necessarily linked to crime. Only a small percentage – about 3% according to some studies – of all drug users commit crime. These tend to be people on heroin and/or crack cocaine, who commit mostly non-violent, acquisitive crimes like theft, shoplifting, burglary and forgery, or who resort to prostitution to help fund their habit.

However, other studies have shown that some heroin and crack cocaine users were committing crimes before they started using such drugs. This would support the view that drug use does not necessarily cause crime; in these situations, a delinquent environment may facilitate drug use, not the other way round.

Moreover, some commentators have pointed out that drug related crime tends to be over-estimated. This is due to a number of factors, including that users of illegal drugs (especially heroin and crack addicts) tend to be arrested more often than non-users.

Although drug use is supposed to be causing a high proportion of property crime, the latter has in fact declined whilst the former has not. According to official government figures based on surveying victims of crime property crime fell by 44% between 1995 and 2007, but there is no evidence of any reductions in the use of heroin, cocaine and crack. It is therefore difficult to maintain an inevitable link between drug use and crime. However, illegal drugs are also linked to crime via the operations of the black Robertet that exists to sustain their availability.

What about alcohol and crime?

Whether alcohol abuse causes crime is similarly debatable.

Some commentators stress the high economic and social costs of alcohol-related violence and disorder, which is most in evidence in town centres at night and weekends. Alcohol abuse is often associated with instances of domestic violence, drink driving, assaults and other violent crime. Alcohol intoxication can repress inhibitions and dampen judgement, which increase the chances of undesirable behaviour. It lessens the capacity to recall one’s actions, thereby decreasing the likelihood of being deterred from committing further undesirable acts. However, what part alcohol plays in criminal behaviour occurring, when weighed against other factors, like one’s personality, emotional and psychological history, family background etc., is difficult to ascertain.

A variety of social and cultural factors are also thought to affect the apparent connection between drinking alcohol and aggressive behaviour, for example expectations around enjoyment and leisure time and notions about masculinity, territoriality, honour and respect.

Although the majority of young people do not drink, under-age binge drinking is an issue of increasing concern, with a minority drinking more, at a younger age.

Moreover, the extension of licensing hours in 2005 has been criticised for encouraging alcohol over-consumption.