“Mr Rose [counsel for the defence] did suggest to you in his closing address that you would get some further help from me when giving you directions in law as to what the word substantially means, where it says substantially impaired his ability to exercise those qualities. I am not going to give you any help on the meaning of the word substantially, because unless it creates real difficulty and you require further elucidation, the general principle of English law is that where an everyday word is used, don’t tell juries what it means. They are bright enough and sensible enough to work it out for themselves, so I am not going to paraphrase substantially. Substantially is the word that is in the Act of Parliament and that’s the word that you have to work with. If it becomes a stumbling block in some way, well at the end of the day, you can send me a note and in those circumstances, I am permitted Page 3 to offer you a little more help, but not at this stage of proceedings.”
“substantially impaired”
“Assuming that the jury are satisfied on the balance of probabilities that the accused was suffering from ‘abnormality of mind’ from one of the causes specified in the parenthesis of the subsection, the crucial question nevertheless arises: was the abnormality such as substantially impaired his mental responsibility for his acts in doing or being a party to the killing? This is a question of degree and essentially one for the jury. Medical evidence is, of course, relevant, but the question involves a decision not merely as to whether there was some impairment of the mental responsibility of the accused for his acts but whether such impairment can properly be called ‘substantial’, a matter upon which juries may quite legitimately differ from doctors. ... This court has repeatedly approved directions to the jury which have followed directions given in Scots cases where the doctrine of diminished responsibility forms part of the common law. We need not repeat them. They are quoted in Reg v Spriggs. They indicate that such abnormality as ‘substantially impairs his mental responsibility’ involves a mental state which in popular language (not that of the M’Naughten Rules) a jury would regard as amounting to partial insanity or being on the border-line of insanity.”
“It is to be remembered that in Byrne … all the doctors agreed that Byrne could be described as partially insane; he was a sexual psychopath who had hideously mutilated a young woman he had killed. In such a case the evidence justifies inviting a jury to determine the degree of impairment of mental responsibility by a test of partial insanity. But it is not a legitimate method of construing an Act of Parliament to substitute for the words of the Act an entirely different phrase and to say that it is to apply in all circumstances. We are sure that this was not the intention of the court in Byrne …, and the phrase was used as one way of assisting the jury to determine the degree of impairment of mental responsibility in an appropriate case, and no doubt to point out that Parliament by the use of the word ‘substantial’ was indicating a serious degree of impairment of mental responsibility.”
“do we think, looking at it broadly as commonsense people, there was a substantial impairment of his mental responsibility in what he did? If the answer to that is ‘yes’ then you find him not guilty of murder but guilty of manslaughter. If the answer to that is ‘no, there may be some impairment but we do not think it was substantial. We do not think it was something which really made any great difference although it may have made it harder to control himself to refrain from crime’, then you would find him guilty as charged.”
“Fourthly, this word ‘substantial’, members of the jury. I am not going to try to find a parallel for the word ‘substantial’. You are the judges, but your own common sense will tell you what it means. This far I will go. Substantial does not mean total, that is to say, the mental responsibility need not be totally impaired, so to speak destroyed altogether. At the other end of the scale substantial does not mean trivial or minimal. It is something in between and Parliament has left it to you and other juries to say on the evidence, was the mental responsibility impaired, and, if so, was it substantially impaired?”
“In R v Lloyd … directions as to the word ‘substantial’, to the effect that (1) the jury should approach the word in a broad commonsense way or (2) the word meant ‘more than some trivial degree of impairment which does not make any appreciable difference to a person’s ability to control himself, but it means less than total impairment’ were both approved.”
“Finally, for the avoidance of doubt, we advise judges that guidance as to the meaning of ‘substantial’ should be explicitly provided for the jury by using one or other of the two meanings in R v Lloyd.”
“This requires you to consider to what extent the defendant’s state of mind differed from that of the ordinary person. Was it so abnormal that the defendant’s mental responsibility was substantially reduced? ‘Substantially’ is an ordinary English word to which you will bring your own experience. It means less than total and more than trivial. Where you draw the line is for your own good judgment.”
“‘Substantially impaired’ means just that. You must conclude that his abnormality of mind was a real cause of the defendant’s conduct. The defendant need not prove that his condition was the sole cause of it, but he must show that it was more than a merely trivial one which did not make any real or appreciable difference to his ability to control himself.”
“The following direction has been approved at a senior level and it is this; the direction on the words ‘substantially impaired’. Your own common sense will tell you what it means. ‘Substantial’ does not mean ‘total’. That is to say the mental responsibility need not be totally impaired, so to speak, destroyed altogether. The other end of the scale, ‘substantial’ does not mean ‘trivial’ or ‘minimal’. It is something in between and Parliament has left it to you to say on the evidence was the mental responsibility impaired and if so, was it substantially impaired?”
“It is, however, clear on analysis that in Lloyd the court rejected the submission that there were two meanings for the word ‘substantially’. In the judgment in Lloyd the word ‘substantially’ carried ‘some’ meaning or ‘a’ meaning. It was accepted in Lloyd that there were different ways of illustrating the same concept and, if necessary, explaining its relevance to the jury. If the court in Egan had intended to convey that the words ‘substantially impaired’ embraced two different concepts or levels of impairment, it would have said so not by citing Lloyd as authority in support, but by distinguishing Lloyd. In the result, just as the court in Lloyd could see no effective difference between the directions in Simcox and Lloyd, the Court of Appeal in Egan could see no difficulty in the deployment of either of the two methods of explanation found in Lloyd.”
“In every case, in colloquial terms, there must, unfortunately, have been something far wrong with the accused, which affected the way he acted … While the plea of diminished responsibility will be available only where the accused’s abnormality of mind had substantial effects in relation to his act, there is no requirement that his state of mind should have bordered on insanity. … In essence, the jury should be told that they must be satisfied that, by reason of the abnormality of mind in question, the ability of the accused, as compared with a normal person, to determine or control his actings was substantially impaired.”
“A person who would otherwise be convicted of murder is instead to be convicted of culpable homicide on grounds of diminished responsibility if the person’s ability to determine or control conduct for which the person would otherwise be convicted of murder was, at the time of the conduct, substantially impaired by reason of abnormality of mind.”