The cases analyzed are Watmore v. Jenkins (1962), R. v. Quick (1973), and R. v. Bailey (1983). It follows from the 'Quick' case that in English law, diabetes is a disease of the mind and so is within the scope of the insanity defense, even though diabetes can be established by medical testimony to be a physical illness. The reason for including diabetes under the rubric of the insanity defense is so the court may retain jurisdiction over treatment, should acquittal result. The courts should have power to ensure medical treatment and supervision for persons acquitted on grounds other than insanity. The doctrine that a plea of automatism (the defendant was not acting voluntarily in the commission of the charged offense) will not be accepted when the accused was reckless by bringing himself/herself into the state of automatism poses problems when applied to diabetes. In 'Bailey,' the court of appeal suggested that the issue of recklessness is to be established on a subjective rather than an objective standard; i.e., did the accused foresee the risks and disregard them. One consequence of the legal doctrine of recklessness is that the well-controlled diabetic is more likely than the patient with poorly controlled diabetes to be convicted of an offense, because it is more likely he/she will experience hypoglycemic episodes. Expert medical evidence must be current and relevant in cases involving diabetic conditions, so that the court may act on accurate and relevant information. Eight references are provided.