This essay evaluates the recent restatement in OʹBrien v Chief Constable of South Wales Police of the law on similar facts in civil proceedings. The two-stage approach propounded in OʹBrien contains a number of conceptual problems. Apparent simplicity was achieved by avoiding fundamental issues underlying this area. Prior to the Criminal Justice Act 2003, judges recognized that the common law similar facts rule had a role to play in both civil and criminal trials; but they gave the rule a wider exclusionary scope in criminal than in civil cases. Adoption of a moral perspective helps to explain this state of affairs. The rule, so it will be argued, protects the legitimacy of trial deliberation by forbidding reliance on an assumption that disrespects the moral autonomy of the person whose conduct is being judged. This moral objection can arise in civil cases; but it arises more frequently and usually with greater force in criminal proceedings. Hence, while there is a need to reserve some judicial power to disallow proof of similar incidents in the civil context, there is usually less reason for the exercise of that power in civil cases than at criminal trials.