自1764年以来,国际习惯法(CIL)已经被纳入英国国内法而不需要任何国家行动。不过,霍夫曼在R v琼斯勋爵(玛格丽特)强调CIL只能作为普通法的发展来源而不是直接的。这种情况下创建刑法所涉及的宪法问题,即议会是唯一合法的器官而不是CIL。这个宪法块放置在CIL成为直接的说:“新CIL有别于传统CIL几个基本的方法。不太相关国家实践,它可以迅速发展,它越来越负责监管国家对待本国公民的方式。许多因素表明,CIL并入国内法律受到不确定性,缓慢,缺乏透明度和缺乏政治审查。销售&克莱门特,辩论需要为了澄清CIL之间的关系和国内法律。Treasa Dunworth指出一种不同的方法,即一些CIL规则直接并入到国内的法律体系,但其他人似乎不那么合法宪法阻塞。有鉴于此,辩论仍需要以决定哪些CIL规则被认为合法自动合并那些阻塞是非法的。
Since 1764, customary international law (CIL) has been incorporated into the domestic law of the UK without the need for any state action. However, Lord Hoffman in R v Jones (Margaret) emphasised that CIL should only be used as a source of development for the common law rather than being directly enforceable. This case involved the constitutional issue of creating criminal laws, namely that Parliament is the only legitimate organ to do so rather than CIL. This constitutional block that is placed on CIL becoming directly enforceable it has been stated that:“The new CIL differs from traditional CIL in several fundamental ways. It is less tied to state practice, it can develop rapidly, and it increasingly purports to regulate a state's treatment of its own citizens.Many factors suggest that CIL’s incorporation into domestic law is plagued by uncertainty, slowness, lack of transparency and lack of political scrutiny. Sales & Clement state that debate is needed in order to clarify the relationship between CIL and domestic law. Treasa Dunworth notes a different approach, namely that some CIL rules are incorporated directly into the domestic legal system but others that seem less legitimate are constitutionally blocked. Even with this in mind, debate is still needed in order to decide which CIL rules are deemed legitimate for automatic incorporation and those that are blocked as illegitimate.