The common law doctrine of mistake of fact or civil law works as denial of offending, but dishonesty works as one of the definitional elements of crimes such as theft and fraud. It is argued in this article that the rulings in R v Barton [2020] 3 WLR 1333 and Ivey v Genting Casinos (UK) (trading as Crockfords Club) [2018] AC 391 do not change the doctrine of mistake of fact or civil law but do change the law in respect of mistakes about what is honest. A defendant whose conduct is taken as dishonest according to community standards may well avoid criminal liability if he was genuinely mistaken about a fact or civil law right. It is submitted that since the doctrine of mistake of fact or civil law is already provided for, the law is not expanded greatly by the rulings in Ivey and Barton which merely bring back the objective test of dishonesty that had long been established before the Ghosh test. The decision in Barton is substantively welcome, even though the change in the law arose from a civil law case where dishonesty was not an issue before the court.

事实错误或民法的普通法学说是否认犯罪，但不诚实是盗窃和欺诈等犯罪的定义要素之一。本文认为，R v Barton [2020] 3 WLR 1333 和Ivey v Genting Casinos (UK) (trading as Crockfords Club) [2018] AC 391中的裁决并未改变事实错误原则或民法但确实要修改关于诚实的错误的法律。根据社会标准被视为不诚实行为的被告，如果他真的对事实或民法权利有误解，则很可能避免刑事责任。认为由于事实错误原则或民法原则已被规定，因此该法并未因《中华人民共和国民事诉讼法》的裁决而大幅扩展。Ivey和Barton只是带回了在Ghosh测试之前早已建立的不诚实的客观测试。巴顿案的裁决实际上受到欢迎，尽管法律的变化源于民事案件，在该案件中，不诚实不是法庭审理的问题。