With the prevalence of WikiLeaks and similar websites, there has been a marked increase in parties seeking to adduce evidence that has been illegally obtained. The problem is not, however, new. This article considers the approach of the criminal and civil courts in the UK to illegally obtained evidence and the approach of arbitral tribunals. Necessarily, because of the confidentiality of commercial arbitration, the latter is mainly a survey of ICSID cases. The UK is consistent across criminal and civil courts generally favouring the admission of the disputed evidence, albeit with sanctions. In the arbitration cases, however, exclusion is more common generally based on the obligation to arbitrate in good faith.