Is ‘stop and search’ effective?

It’s five years since London was struck by the worst rioting in a decade. The riots resulted in five deaths and over 200 injuries. In the aftermath of the riots, 1,292 rioters were handed custodial sentences totalling 1,800 years.

A number of inquiries were held to identify the underlying causes of the riot. Once possible cause cited was the use of stop and search powers, which have been disproportionately used against people from ethnic minority backgrounds. It was argued that this created distrust and ultimately anger in the police in ethnic minority communities.

After the riots, the then Home Secretary, the Rt Hon Theresa May MP, ordered the police to reduce their use of stop and search powers. However, some proponents of stop and searches have argued that they were effective, and the recent reduction has led to an increase in crime.

A troubled history

Under section 4 of the Vagrancy Act 1824, police officers were allowed to search civilians when they were deemed to be behaving suspiciously. This law became known as the ‘Sus’ law; short for ‘suspicious’ person.

This law caused significant controversy in the 1980s when it was employed abundantly by the Metropolitan Police. In early April 1981, Operation Swamp - an attempt to cut street crime in Brixton - used the Sus law to stop more than 1,000 people in six days.

Soon after, rioting broke out in Brixton. The riots resulted in over 300 injuries but no deaths. In his official report into the riots, Lord Scarman identified Sus law as a causal factor of the rioting. In response, the Government repealed the Sus law in August of 1981.

However, in 1984 the Government introduced the Police and Criminal Evidence Act (PACE) which permitted police officers to search civilians without arrest where there was “reasonable” suspicion.  PACE is the law currently used by police officers in order to carry out the vast majority of searches of a person without arrest.

PACE provoked significant controversy following the 2011 riots when its disproportionate use against ethnic minority individuals was identified as one cause of the riots by a number of inquiries. Following the then Home Secretary’s, order for the police to significantly reduce their use of the powers, stop and searches fell from a peak of 1.2 million in 2010-11 to 539,000 in 2014-15.

Detecting crime

However, some such as the Metropolitan Police have been critical of the reduced usage of stop and search. They argue that the reduction in stop and searchers has coincided with a significant increase in crime, particularly knife crime.

Proponents of stop and search laws argue that it allows police officers to detect crime. They claim that police officers can frequently have reasonable suspicion that a person is committing a crime, but not enough evidence to arrest the suspect. In such circumstances, it can be impractical for police officers to seek a warrant to search a suspect.

The most useful evidence surrounding detection is the proportion of individuals arrested following a stop and search. Since the Macpherson Inquiry, which examined the practises of the Metropolitan Police following the murder of Stephen Lawrence, police officers have been compelled to keep a record of stop and searches and subsequent arrests.

The graph below shows the proportion of stop and searches, under PACE, which resulted in arrests. This arrest rate dropped from a high of 13% in 2003-04 to lows of 9% between 2009 and 2012. The arrest rate currently stands at 12%. The overall arrest rate suggests that stop and searches are not a particularly effective form of detecting crime.


Proportion of searches using PACE leading to arrest (2003-2014)

Source: Home Office (2016)

The arrest rate does, however, vary significantly depending on the reason that a person was searched. Twenty per cent of people who were searched because a police officer suspected that they held an offensive weapon were subsequently arrested. In contrast, only 9% of people who were searched on suspicion of possessing drugs were arrested.   

Deterring crime

A low arrest rate in itself does not necessarily mean that stop and search does not work. Proponents of stop and search also argue that its use can deter and prevent crime. They argue that the powers can effectively disrupt crime, particularly in relation to terrorism.

Estimating the number of crimes prevented by stop and search powers is inherently difficult. The most recent Home Office study into this used the British Crime Survey to estimate the number of crimes which were susceptible to disruption by searches. These offenses include burglary, vehicle thefts, bicycle theft, robbery and wounding. The study estimated that stop and searches reduced these crimes by 0.2%. It should be noted that the Home Office study did not include crimes under the Misuse of Drugs Act. However, this research does suggest that stop and searches have only a very small effect in preventing crime.

Earlier this year, the Home Office released research under a Freedom of Information request into Operation Blunt 2. Operation Blunt 2, which began in the spring of 2008, was an attempt to reduce knife crime in London. It involved a significant increase in stop and searches in some London boroughs. The official evaluation looked at ten London boroughs which saw 300% increase in weapon searches by the police, up from 34,154 in the year before to 123,335 in the first year of the Operation.

It compared the crime rates in these boroughs to 16 other London boroughs, which saw a much smaller increase in weapon searches over the same period. The researchers examined nine different measures of crime including assaults involving a knife, robbery, and weapons and drug possession offences. Their analysis found that “no statistically significant crime-reducing effect from the large increase in weapon searches during the course of Operation Blunt 2. This suggests that the greater use of weapons searches was not effective at the borough level for reducing crime.”


Since 2011, there has been a significant reduction in the use of stop and search powers. A number of inquiries have suggest that stop and search created distrust in the police in ethnic minority communities. However, it is possible that this distrust might be an acceptable price if stop and searches were particularly effective at reducing crimes. The evidence does not suggest this is the case. The use of stop and search does not seem to detect crime nor deter it.

James Dobson is a researcher at Bright Blue