Visible police patrols of just four hours a week cut crime by more than 20 per cent, a Cambridge study has shown.
A six-month experiment at 57 London Underground stations found that four 15 minute patrols each day, four days a week, caused a drop in crime of 21 per cent.
A massive 97 per cent of the drop was recorded when officers weren’t actually present, researchers dubbed the ‘phantom effect’.
Visible police patrols at tube stations were responsible for a 21 per cent drop in criminal acts
Researchers from Cambridge University studied the impact four 15-minute patrols at a tube station would have on crime levels each day. The study found crime levels reduced even after officers had left the station
The experiment showed the long-lasting effect of short bursts of patrols can be, said the Cambridge University team behind it.
Study co-author, Prof Lawrence Sherman, said: ‘The total crime prevention benefit of police patrols may be greater when they are absent than when they are present.
‘In the London Underground experiment we see a huge residual effect of brief appearances by patrolling officers after they leave.
‘This phantom effect suggests that crime declines when potential offenders are apprehensive about a possible police presence based on recent patrolling patterns – even when there are no police in the vicinity.
‘In London stations, it may be that more professional kinds of offenders are particularly sensitive to changes in police presence, such as pickpockets and distraction thieves.
‘This London Underground paradox could have implications for debates on police priorities in an age of austerity, such as the benefits of investigating past crimes compared with the benefits of preventing future crimes.’
A total of 115 of the Underground’s most crime-ridden stations, such as Russell Square, Oxford Circus and Earl’s Court were chosen for the test with 57 of those randomly chosen to get patrols between 2011 and 2012.
While the experiment was running, a total of 3,549 calls to police from the platform came from stations without patrols, compared to 2,817 in the stations with a sporadic police presence.
Based on their results, the researchers are now recommending more patrols to reduce crime.
Dr Barak Ariel, fellow in experimental criminology at the University of Cambridge, said: ‘The more that uniformed police have been there, and the more recently, the less likely the future crimes may be to occur.
‘For every hour police spend in cars driving to answer non-emergency calls, we can now see that investment in reactive policing as a choice, not a duty.
‘If the question is whether proactive patrols do the most good where the most harm is likely to occur, communities might finally move to reallocate preventive patrols to locations where we have documented their optimal effects, as long recommended by the National Research Council.’
The platform patrols were the first of their kind in the Underground’s 155-year-long history.
Researchers said choosing platforms gave them a glimpse of how effective police patrols can be by using an ‘uncontaminated’ environment.
Dr Ariel said: ‘Platforms are small, stable and confined places with finite entry and exit points. These characteristics make them optimal for measuring the localised deterrence effects of police patrols.
‘We wanted to measure what happens when police patrols are introduced into an urban environment for the first time in over 150 years.’
The team targeted ‘hot spots’ – areas where crime is more concentrated, and preventative patrols can have greatest effect – by ranking stations based on the previous year’s crime rates.
Researchers also honed in on ‘hot hours’ and ‘hot days’ – for example, data showed platforms experienced more crime and calls to police from Wednesday to Saturday between 3pm and 10pm.
Twenty uniformed BTP officers were selected and trained to work exclusively on patrolling the platforms of the ‘treatment’ stations during ‘hot’ days and hours.
Each two-person unit was allocated between three and five stations, with platforms patrolled for fifteen minutes four times a day.
Officers were asked to conduct these patrols in a random or unpredictable order within the ‘hot hours’, and encouraged to engage with the public while patrolling.
Police were most effective at preventing platform crime during periods and days when patrols were scheduled – but just 3 per cent of that reduction came when officers were actually scheduled to patrol.
The researchers also found ‘regional’ effects – crime in the rest of the station fell almost as much as crime on platforms during the four days when regular patrols were deployed.
Dr Sherman added: ‘Our findings indicate that consistent patrols can cause large reductions in both crime and emergency calls in areas that have never before been proactively patrolled by police in this way.’