ALT We aim to test the impact of a new national curriculum for public and personal safety training (PPST) developed by the College of Policing, which aims to reduce the use of force by police. We conduct a large-scale Stepped Wedge Pragmatic Controlled Trial with a single police force and 1843 participating police officers. Officers were assigned to be trained during a particular week of the year. We find statistically significant reductions in the use of force by police officers as a result of the training. These effects are a reduction of between 8.0% and 10.9% in the propensity to use force in a given week compared to the counterfactual. The effect is accompanied by a significant reduction in the likelihood of injury to civilians, and no rise in the risk of harm to officers. We conclude that the PPST curriculum appears effective at reducing use of force by police in a large scale, robust trial.