Great Britain's 1983 "Christmas Crusade" against drunken drivers, during which the police of England and Wales administered an average of 1350 breath tests daily, is discussed. Although not deliberately planned and organized, the campaign, fueled by press reports, was perceived by many observes to be a national organized deterrent effort. To test the hypothesis that the crusade reduced drunken driving, the index of total automobile crash-related fatalities was used in the analysis. Results showed that the index declined significantly during the month of the crusade, providing support for the hypothesis of deterrent effect. The experience of the Christmas Crusade reinforces the expectation that deterrent interventions involving highly publicized campaigns increasing the certainty of punishment for illegal behavior can be successful over a limited period of time.