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, although preventive measures and policing are necessary, but these should be democratically controlled.

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

Theoretical

1. 'The basic triangle of relations which is the proper subject-matter of criminology [is] - the offender, the state and the victim' (Young, 1986) (since altered to include society at large, see The Square of Crime)
2. Theoretical explanations must be symmetrical - there must be the same explanation for social action and reaction.
3. 'Man is a creator of human nature' (Young, 1987), and therefore explanations of crime should not be deterministic and people should be seen as being responsible for their actions.

Political

1. Crime is a real problem and especially to working-class people who suffer disproportionately from personal crime, such as robbery, assault, burglary and rape.
2. The 'left' should attempt to develop a credible (populist?) approach to crime control in order to prevent the 'right' from having a monopoly of the 'crime problem'.
3. The purpose of theorizing should be to make practical interventions into law and order issues.
4. In order to reduce crime there is a need to achieve a higher level of cooperation between police and public, and this will be best achieved by a democratization of local control of the police."