INTRODUCTION In this project, I will evaluate whether the current insanity defense law is ineffective, outdated, and in need of reform. I will do this by considering some criticisms of the insanity defense under the M'Naghten Rules by academics such as Peter Blood and others, as well as examining possible reform of the law in the Scoping paper on insanity and automatism. My main objective is to uncover particular parts of the law that urgently need reform such as sleepwalking, diabetes and the distinction between external and internal factors, through comparison of key conflicting case law. I would also like to draw attention to the legal definition of insanity and the now outdated M'Naghten (test) rules. The concept of insanity as a defense was established in the early 18th century in the Arnold case (1724) and was further developed in the late 18th century in the Hadfield case (1800), but the standard test of criminal responsibility was formed only after the case of Daniel M'Naghten (1843). This case established the special verdict of "not guilty by reason of insanity" which leaves the Ds under the control of the courts. Another issue, criticized by Peter Blood is that the burden of proof is on the D, meaning that the D must prove his insanity defense on the balance of probabilities and not beyond a reasonable doubt. The legal definition of insanity: The legal definition of insanity has not changed since 1842. The Law Commission of 1965, the main body proposing changes, included insanity in the 10th reform programme. They said But the commission created the defense of diminished liability instead of what I think is wrong. Over the years, academics have identified uncertainty in the insanity defense… mid-paper… internal or external cause . In the case of T (1990), where the court could not decide whether the post-traumatic stress resulting from the rape was an external or internal factor. The opinions of psychiatrists also differed. In Wiseman (1972), where psychiatrists claimed that the murder of his two sons occurred in a "dissociative state" leading to unconscious involuntary actions. Examples of external causes may include: a blow to the head, a sneeze (Whooley), an attack by a swarm of bees (Hill v Baxter) or an effect of drugs (Lipman). According to the scoping papers the English legal system has designated the distinction in Hennesey (1989): Consequently, It is very difficult to distinguish which factors are responsible for the crime committed which leads to injustice. This can be seen in cases dealing with problems with sleepwalking.