Campaigns against miscarriages of justice have played a role not just in exposing individual cases of injustice but also in helping to shape criminal justice policy itself. The means by which such campaigns manage to achieve degrees of ‘success’ are therefore of criminological significance. Using the term ‘miscarriages of justice’ to embrace both ‘wrongful convictions’ and the failure of agencies to act appropriately (‘not doing enough’), the article proceeds to define the various ways in which such campaigns might be said to have ‘successful’ outcomes. Using documentary analysis and a programme of interviews with key players, the article then examines the ‘critical success factors’ behind campaigns against miscarriages of justice. It concludes that two factors have been the key to successful campaigns against miscarriages of justice: on the one hand the ability of campaigns to access the social resources and social capital associated with campaigning networks; on the other hand the ability of victims and families associated with injustices to provide the resilience and cohesion which campaigns typically need to achieve goals.