Left realism emerged in criminology from critical criminology as a reaction against what was perceived to be the left's failure to take a practical interest in everyday crime, allowing right realism to monopolize the political agenda on law and order. Left realism argues that crime disproportionately affects working-class people, but that solutions that only increase repression serve to make the crime problem worse. Instead they argue that the root causes of crime lie in relative deprivation, and that although preventive measures and policing are necessary, they should be placed under democratic control.

Pat Carlen (1992) suggests that the main tenets of left realism are theoretical and political:

Theoretical

Political

Left realism emerged from critical criminology taking issue with "the two major socialist currents in criminology since the war: reformism and left idealism", criticising 'the moral panics of the mass media or the blatant denial of left idealism'

Writing years later, Jock Young summed up critical criminology's criticism of establishment criminology by saying

The essential flaw of establishment criminology is, of course, the attempt to explain crime without touching upon reality, constantly to distance explanation from basic social and economic problems of a divided society.

Left Realism set down a marker in the United Kingdom with the work of Lea and Young (1984) as representative of a group of academics: Richard Kinsey, John Lea, Roger Matthews, Geoff Pearson, and Jock Young. The group saw themselves as facing up to the challenge thrown down by Ian Taylor in Law and Order: Arguments for Socialism for the left to take crime seriously.