These events may be related. The London heroin market is stable and relationships between dealers and users are reliable and long-term. By removing established dealers, the police may have severely disrupted the local heroin market, inadvertently replacing known dealers selling drugs of known purity with 'new entrepreneurs' selling drugs with potentially fatal characteristics.
The Swiss police's blitz on 'Needle Park', Zurich, last year may have had harmful effects also.
The success of police activity should not be judged on the number of arrests, but on the influence of these arrests on drug use and the harm arising from this habit. Without careful consideration of the full effects of police interventions on drug markets, unfortunate outcomes, such as those in King's Cross, might regrettably come to be expected rather than be surprising.
University of York