Zero Tolerance. Chris Ledgard visits New York to explore the origins of zero tolerance policing, arguably responsible for cutting New York's murder rate by half in the 1990's. But can such spectacular results in the fight against violent crime really be traced back to tackling litter, broken windows and graffiti?

Zero tolerance policing has its origins in the criminological theory know as "broken windows." According to this theory, serious crime can be tackled at grass roots level by improving the quality of life of a community. George Kelling, academic and architect of "broken windows" talks to Chris Ledgard about the origins of the idea, and the way it was used in the fight against crime in the 1980's and 1990's.

Chris also meets William Bratton, onetime head of the NYPD and hailed as America's top cop when his zero tolerance policing appeared to cut New York's murder rate by half. But did clamping down on street traders and squeegie men really tackle serious crime, or was something else happening to the Big Apple? Show less