JUDGMENT of Ms. Justice O’Malley delivered the 7th day of February 2017.
1. This appeal concerns the burden and standard of proof in a case where a person charged with murder seeks to rely on the defence of diminished responsibility created by s.6(2) of the Criminal Law (Insanity) Act, 2006. The Act requires an accused to “establish” that, by virtue of the section, he or she is “not liable to be convicted” of murder. The appellant sought to rely upon this provision but was, on the 26th June, 2013, convicted of the murder of Mr. Eoin Ryan on the 7th June, 2011. An appeal to the Court of Appeal was unsuccessful. He was subsequently granted leave to appeal to this Court on the question whether the section had been correctly interpreted. In summary, the appellant contends that the burden imposed on the defence by the Act should be construed as requiring him only to raise a reasonable doubt as to his liability to be convicted of murder, and that he was incorrectly held to have been obliged to prove on the balance of probabilities that his responsibility was diminished by reason of the matters set out in the legislation.
2. There is no dispute about the facts of the case and the appeal was presented on the basis of the following agreed summary rather than by reference to the transcript.
3. This somewhat sparse information is amplified in the judgment of the Court of Appeal (The People at the Suit of the Director of Public Prosecutions v. Joseph Heffernan  IECA 310). It appears that both Dr. O’Mahony and Dr. Linehan were called by the prosecution and that the defence did not go into evidence.
“The appellant was convicted of murder after a nine day trial in the Central Criminal Court before the Honourable Mr. Justice McCarthy. It was common case during the trial that on the 7th day of June, 2011 in Cappabeg, Barefield, Ennis he unlawfully caused the death of the deceased, Mr. Eoin Ryan. The main issues in the trial therefore related to whether he intended to kill or cause serious injury to the deceased or whether he was not guilty by reason of insanity, or guilty of manslaughter by reason of diminished responsibility pursuant to sections 5 and 6 of the Criminal Justice (Insanity) Act, 2006, respectively.
The facts leading up to the death of the deceased were that on the evening of the 6th June, 2011 the deceased was drinking with friends in Cruises bar in Ennis, where he met the appellant and they had a brief conversation. Without saying goodbye to his friends the deceased left the bar and then shortly afterwards the appellant left also. At approximately 6 am the following morning the Gardaí received a phone call from the appellant stating that he had killed a man, that the devil was in him and that he came on to the appellant and he killed him.
Gardaí arrived to find the appellant in a distressed state and he brought [them] up into his field where he showed them a water barrel containing the remains of the deceased. Upon interview, the appellant accepted that he had killed the deceased but denied intending to kill a person, stating that the devil had taken over the deceased and it was only after he had beaten the deceased to death that the devil left him and he had realised what he had done to the young man. He then asserted that he had spoken to Jesus and Jesus told him to ring the Gardaí.
The appellant was seen initially by Dr. O’Mahony, a local consultant psychologist, who attended at the Garda station on the same day. He gave evidence that in his view the [appellant] was delusional and suffered from perceptional disturbance. The appellant was subsequently reviewed by Dr. Linehan, who gave evidence that there were discrepancies in his evidence and he gave inconsistent accounts between interviews.
The appellant was afforded the opportunity to prepare his own defence psychiatric report which he availed of but which was not ultimately relied upon at trial.”
4. Dr. O’Mahony said that, on the morning he saw him in the garda station, the appellant had a firmly held delusional belief that, rather than killing a man, he had done the world a service by removing the devil. He stated that the appellant had no insight, or an impaired insight, into the reason why he was arrested.
5. Dr. Linehan, who subsequently reviewed the appellant on behalf of the prosecution, pointed to certain inconsistencies in the appellant’s accounts at interview with her. She said that she found no evidence of formal thought disorder. The results of one test suggested that he was exaggerating but not feigning his symptoms, and she considered that he did have symptoms of an adjustment disorder characterised by depressive symptoms following the death of his father. In relation to a possible diagnosis of schizophrenia, she said that some symptoms displayed by the appellant supported such a diagnosis, some were not inconsistent with it and some did not support it. Ultimately her opinion was that while he was suffering from a mental disorder within the meaning of the legislation, it was not such as would render him unable to refrain from committing the act. Nor was it such as would, in her opinion, substantially diminish his responsibility. Under cross-examination, she expressed the view that the killing was explicable by intoxication.
6. Two defences were left to the jury by the trial judge - diminished responsibility and, on the basis of Dr. Linehan’s evidence, intoxication. On diminished responsibility, the defence made a formal application (in the knowledge that the Court of Criminal Appeal authority of The People (Director of Public Prosecutions) v. Smyth Snr.  3 IR 688 was against the proposition) that the jury should be told that that the legal burden cast on the defence under the Act was only to raise a reasonable doubt. The trial judge refused the application and directed the jury that it was a matter to be proved by the defence on the balance of probabilities. The appellant was convicted.
7. For the purposes of this case it is necessary to consider certain of the provisions relating to the defence of insanity as well as diminished responsibility. The former is dealt with in s.5 of the Act, which provides in relevant part as follows:
8. Section 5(4) reads as follows:
“5. - (1) Where an accused person is tried for an offence and, in the case of the District Court or Special Criminal Court, the court or, in any other case, the jury finds that the accused person committed the act alleged against him or her and, having heard evidence relating to the mental condition of the accused given by a consultant psychiatrist, finds that -
the court or the jury, as the case may be, shall return a special verdict to the effect that the accused person is not guilty by reason of insanity.”
9. A “mental disorder”, as defined in s.1, includes mental illness, mental disability, dementia or “any disease of the mind”.
“(4) Where on a trial for murder the accused contends -
the court shall allow the prosecution to adduce evidence tending to prove the other of those contentions, and may give directions as to the stage of the proceedings at which the prosecution may address such evidence.”
10. Section 6 is the provision that introduced into Irish law the concept of diminished responsibility. It does so in the following terms:
11. It is also relevant to note the definition of murder in s.4 of the Criminal Justice Act, 1964:
12. In The People (at the Suit of the Attorney General) v. Dwyer  I.R. 416, a murder case involving issues of self-defence, the Supreme Court held that the effect of this section was that the prosecution bore the onus of establishing the necessary intent and also an onus of proving that the presumption in s. 4 (2) had not been rebutted.
“6. - (1) Where a person is tried for murder and the jury or, as the case may be, the Special Criminal Court finds that the person -
the jury or court, as the case may be, shall find the person not guilty of the offence but guilty of manslaughter on the ground of diminished responsibility.
(a) did the act alleged,
(b) was at the time suffering from a mental disorder, and
(c) the mental disorder was not such as to justify finding him or her not guilty by reason of insanity, but was such as to diminish substantially his or her responsibility for the act,
(2) Subject to section 5(4), where a person is tried for the offence specified in subsection (1), it shall be for the defence to establish that the person is, by virtue of this section, not liable to be convicted of that offence.”
The judgment of the Court of Appeal
13. The Court of Appeal (in a judgment delivered by Edwards J.) considered that the interaction between ss. 5 and 6 of the Act was crucial to the determination of the burden and standard of proof under s.6. The new defence was not a “stand alone” defence, and its availability was directly referable to the criteria for establishing insanity. It would be absurd and unworkable if the two sections carried differing interpretations of the burden or standard of proof.
14. The judgment therefore paid close attention to the history of the law relating to insanity from M’Naghten’s Case (1843) 10 Cl. & Fin. 200 onwards. It noted the argument made by many academics, and accepted to an extent by the Canadian Supreme Court in R v. Chaulk  3 S.C.R. 1303, that the common law rules as to the standard and burden of proof in relation to the defence of insanity were anomalous and difficult to reconcile with the presumption of innocence. However, the Court rejected the submission that the Oireachtas, by making no express reference to the burden of proof in s. 5, intended thereby to discard those common law rules. It considered that there was nothing in the Act to suggest that the Oireachtas believed that traditional policy justifications for the rules - whether arising from concern about sane people escaping from criminal liability on the basis of tenuous insanity pleas, or from the great difficulty in proving beyond reasonable doubt that an accused person is sane - were obsolete. In those circumstances the Court of Appeal held that the use of the word “establish” in s.6(2) meant that the accused bore the burden of persuasion to the same standard as would apply if he or she was relying on the defence of insanity - that is proof on the balance of probabilities.
Submissions in this appeal
15. The appellant does not disagree with the analysis of the Court of Appeal in relation to the insanity defence under s.5, but disputes the analysis resulting in the finding that diminished responsibility is so closely linked to insanity that the same rules must apply.
16. The argument made is that this is a new statutory defence that did not exist at common law. The general rule in a criminal trial, as emphasised in McGowan v. Carville  I.R. 330 and The People (at the Suit of the Attorney General) v. Quinn  I.R. 366, is that the prosecution must prove guilt, while the accused is not obliged to prove anything. The prosecution must also disprove most of the defences available at common law. Section 6 of the Act does not expressly state that this burden is shifted to the defence, and does not address the standard of proof. It is submitted that, having regard to the legislative silence on this issue, the general rule should apply and the use of the word “establish” should be seen as imposing only the burden of raising a reasonable doubt as to the liability of the accused to be convicted of murder. Otherwise, counsel submits, an accused person could be convicted of murder even if the jury harbours a reasonable doubt as to his or her guilt of that offence.
17. In addressing issues of policy, the appellant submits that the result of the defences of insanity and diminished responsibility are significantly different. If successful, the former clears the accused of all culpability. Policy considerations therefore require the placing of a burden of proof on the accused in insanity cases since, if all that was necessary was to raise a doubt, persons who carried out intentional killings could be found not guilty by reason of insanity and would then be discharged almost immediately. By contrast, a successful defence of diminished responsibility still results in a criminal conviction (for manslaughter) and the likelihood of a prison sentence. It is submitted that this distinction means that the same policy justification for a reverse onus cannot apply.
18. The appellant takes issue with the argument that to impose the burden of proof on the prosecution in cases of diminished responsibility would be impracticable or unfair, arguing that many trials involve questions of intent and that in such cases it is normal for the prosecution to have to rely on inferences to be drawn from the surrounding evidence.
19. With reference to the mental element in murder, it is pointed out that in The People (at the Suit of the Attorney General) v. Dwyer the Supreme Court held that the onus of proof resting upon the prosecution included the onus of proving beyond reasonable doubt that the presumption as to intent set out in s. 4 of the Criminal Justice Act, 1964, had not been rebutted. It is argued that if an accused has to prove that his responsibility was substantially reduced, the prosecution will be relieved of the burden of proving intention to kill or cause serious injury. In a similar vein it is suggested that if the Court of Appeal interpretation is correct, an accused who wishes to avail of the defence will have to first prove that he or she killed the deceased and that he or she was not insane.
20. As an alternative submission, the appellant relies upon the authorities relating to the strict construction of penal statutes to argue that there should be no presumption that the Oireachtas intended to alter the ordinary rule that the prosecution bears the burden of proof. Additionally it is submitted that the interpretation contended for by the appellant is required by the double construction rule of statutory interpretation in order to ensure a constitutionally permitted outcome.
21. The respondent submits that where the accused raises a defence of either insanity or diminished responsibility, it is for the prosecution to prove, beyond reasonable doubt, the unlawful killing and the intention to kill or cause serious injury. However, it is for the accused to establish that at the time he or she was suffering from a mental disorder to the relevant extent. In imposing that burden in the case of diminished responsibility the Oireachtas was amending, but not abandoning, the common law position whereby it was for the defence to prove the existence of a mental disorder. It is submitted that there is no authority for the proposition that the imposition of a persuasive burden on the defence would contravene the Constitution.
Defences - the general principle
22. The People (at the Suit of the Attorney General) v. Quinn concerned, in part, the burden of proof in a manslaughter trial where the accused gave evidence that he had acted in self-defence. The Court of Criminal Appeal took the view that the trial judge had correctly charged the jury in telling them, in effect, that where self-defence was put forward it was “sufficient if it be established in such a way as to raise a doubt as to the guilt of the accused in the mind of the jury”. On appeal to the Supreme Court, the sole judgment was given by Walsh J. who said (at p. 382 of the report):
23. The specific reference to insanity as an exception will be noted, as will the use of the word “established” as importing a burden on the defence in that context.
“In the opinion of this Court the directions of the learned trial Judge introduced such an element of doubt on the question of the onus of proof that the conviction cannot be allowed to stand…
When the evidence in a case, whether it be the evidence offered by the prosecution or by the defence, discloses a possible defence of self-defence the onus remains throughout upon the prosecution to establish that the accused is guilty of the offence charged. The onus is never upon the accused to raise a doubt in the minds of the jury. In such case the burden rests on the prosecution to negative the possible defence of self-defence which has arisen and if, having considered the whole of the evidence, the jury is either convinced of the innocence of the prisoner or left in doubt whether or not he was acting in necessary self-defence they must acquit. Before the possible defence can be left to the jury as an issue there must be some evidence from which the jury would be entitled to find that issue in favour of the appellant. If the evidence for the prosecution does not disclose this possible defence then the necessary evidence will fall to be given by the defence. In such a case, however, where it falls to the defence to give the necessary evidence it must be made clear to the jury that there is a distinction, fine though it may appear, between adducing the evidence and the burden of proof and that there is no onus whatever upon the accused to establish any degree of doubt in their minds. In directing the jury on the question of the onus of proof it can only be misleading to a jury to refer to ‘establishing’ the defence ‘in such a way as to raise a doubt’. No defence has to be ‘established’ in any case apart from insanity. In a case where there is evidence, whether it be disclosed in the prosecution case or in the defence case, which is sufficient to leave the issue of self-defence to the jury the only question the jury has to consider is whether they are satisfied beyond reasonable doubt that the accused killed the deceased (if it be a case of homicide) and whether the jury is satisfied beyond reasonable doubt that the prosecution has negatived the issue of self-defence. If the jury is not satisfied beyond reasonable doubt on both of these matters the accused must be acquitted.”
Reverse onus cases - the Irish authorities
24. Article 38.1° of the Constitution provides that “no person shall be tried on any criminal charge save in due course of law”. It is well-established that this provision encompasses the presumption of innocence. However, that does not mean that an accused person can never be subjected to a burden of proof on some issue in the trial.
25. To begin with, there is a long-established presumption of law that the accused person is sane. In The Attorney General v. O’Brien  I.R. 263 the Court of Criminal Appeal accepted the following passage from Stephen’s Digest of the Criminal Law as a correct statement of the law:
26. In that case the defence of insanity failed. The Court found that there was no misdirection by the trial judge in not putting the case of “irresistible impulse” before the jury, because there was no evidence to ground it.
“Every person is presumed to be sane, and to be responsible for his acts. The burden of proving that he is irresponsible is upon the accused person; but the jury may have regard to his appearance and behaviour in Court.”
27. Similarly, in The Attorney General v. Boylan  I.R. 449 the Court of Criminal Appeal rejected the submission that the jury should have been instructed that if an accused gave evidence tending to rebut the presumption of sanity then the jury should acquit if they had a reasonable doubt on the issue. The Court referred to the opinion of the judges in M’Naghten’s Case that the presumption continues until “the contrary is proved to the satisfaction of the jury, and clearly proved.”
28. A reverse onus may arise in other contexts, usually by virtue of legislation. In O’Leary v. The Attorney General  1 I.R. 254 this Court considered a challenge to the constitutionality of s.24 of the Offences Against the State Act, 1939. The section provided that in a trial of a charge of membership of an unlawful organisation, proof to the satisfaction of the court that an “incriminating document” as defined in the Act was found in the possession or control of the accused
29. The plaintiff, a person who had been convicted of membership of an unlawful organisation, sought a declaration that the section infringed the constitutional right to a trial in due course of law, and in particular violated the presumption of innocence, by placing upon him the burden of disproving his guilt. His argument was rejected by the Supreme Court, which held that proof of possession of the document amounted to evidence only and not proof of membership. Its probative value would depend on the circumstances and did not compel a court to convict. The Act did not, therefore, displace the presumption of innocence.
“shall, without more, be evidence until the contrary is proved that such a person was a member of the said organisation…”
30. The People (Director of Public Prosecutions) v. Smyth Snr.  3 IR 688 was concerned with the burden of proof imposed on an accused by the provisions of s.29 of the Misuse of Drugs Act 1977 (as amended). The section provides that, where the prosecution proves that the accused was in possession of a controlled drug,
31. In its discussion of the correct approach to directing a jury on this issue, the Court of Criminal Appeal observed that the provision in question was not unique, and referred to the defences of insanity and diminished responsibility, as set out in the Act of 2006, by way of comparison. At p. 694 the Court said:
32. The Court of Criminal Appeal had been addressed on the compatibility of a reversed burden of proof with Article 6(2) of the European Convention on Human Rights and Fundamental Freedoms, and noted the views of the House of Lords as expressed in R. v. Lambert  2 AC 545 (discussed below). However, it considered that the proper construction of the burden of proof derived from Article 38.1° of the Constitution. The presumption of innocence is a fundamental principle of the criminal justice system, but a decision by the Oireachtas that an evidential burden should be cast on an accused in relation to a particular element does not of itself infringe that principle. However, where the burden relates to an element of the offence as opposed to a special defence, the necessary inference that the statute intended to cast a burden on the accused is not easily made.
“it shall be a defence to prove that:-
33. In an important passage the Court said:
34. On the issue in the case before it the Court held that s.29 of the Misuse of Drugs Act, 1977, validly imposed a burden on the accused to prove the existence of a reasonable doubt as to his state of mind in relation to the controlled substance in his possession.
“The court notes that bearing the burden of proving a defence as a probability could have the effect that in respect of an element of the offence an accused person might raise a doubt as to his guilt, but not establish it as a probability. This might lead to a situation where the charge was not proven as to each element of the offence beyond reasonable doubt, but nonetheless the accused could be convicted. That would not be right. Proof of a guilty mind is integral to proof of a true criminal offence, in distinction to a regulatory offence.”
The European Convention on Human Rights and Fundamental Freedoms
The United Kingdom authorities
35. Article 6(2) of the European Convention on Human Rights and Fundamental Freedoms entrenches the position of the presumption of innocence in every trial. The compatibility of presumptions creating a reverse onus with this Article was dealt with in the leading authority Salabiaku v France (1988) 13 EHRR 379 where the Court of Human Rights said:
36. The concept of diminished responsibility as a partial defence to murder originally developed as part of the common law of Scotland. There seems little doubt but that under Scottish law the burden in relation to the defence lay on the defence. Thus, in H.M. Advocate v. Braithwaite (1945) J.C. 55, the jury was instructed in the following terms:
37. Interestingly, the Scottish Law Commission published a Draft Proposal in January, 2003, ( SLC 122 (DP)), in which it recommended that the accused should bear an evidential burden only in relation to both insanity and diminished responsibility. However, its view had altered by the time it published its final Report on the 15th July, 2004, (Insanity and Diminished Responsibility  SLC 195 (Report)). The reason for the change of mind was the practical difficulty for the prosecution in obtaining evidence that the accused was mentally normal at the time of the offence. This would be particularly acute if the accused refused to undergo a mental examination. The same issues did not arise in relation to other defences such as self-defence or provocation. In most of those cases, proof of the defence would be given by evidence of the accused’s actions and reactions to external events closely related to the actus reus. The Commission was of the view that it was not disproportionate to impose a burden on the prosecution to disprove such defences, since it would be possible to seek out evidence of the relevant external events. Where, however, the defence is based on a claim of mental disorder there may not be any such evidence.
“If the Crown have established that the accused did this thing, it is not for the Crown to go further and show that he was fully responsible for what he did; it is for the accused to make good his defence of partial irresponsibility, and that means that he must show you that the balance of probability on the evidence is in favour of the view that his accountability and responsibility were below normal.”
38. The defence was adopted into English law by s. 2 of the Homicide Act 1957, which originally read as follows:
39. The statutory defence has since been significantly recast by the Coroners and Justice Act, 2009. However, for present purposes it is the authorities on the 1957 Act that are relevant.
(3) A person who but for this section would be liable, whether as principal or accessory, to be convicted of murder shall be liable instead to be convicted of manslaughter.
40. An early authority on the Act, R. v. Dunbar  1 Q.B. 1, established that the interpretation of the burden of proof in English law was the same as in Scotland.
41. After the enactment of the Human Rights Act in 1998, a number of challenges were mounted in the United Kingdom on the basis that the imposition of a legal or persuasive burden of proof on the defence in a criminal trial constituted an infringement of Article 6(2). In R. v. Lambert, Ali and Jordan  EWCA Crim 3542 the Court of Appeal considered three separate cases involving a reverse onus of proof and its impact on the presumption of innocence. Two of the appeals, Ali and Jordan, concerned unsuccessful claims of diminished responsibility in murder while Lambert was a drugs case.
42. Reference was made in the judgment of the Court to the “golden thread” identified by Viscount Sankey LC in Woolmington v. Director of Public Prosecutions  AC 462, and it was said that the common law is “fiercely resistant” to a burden of proof being placed on a defendant. However, the Court of Appeal stated that there was another “equally glittering” thread. Proof of the commission of an offence requires proof of a guilty mind, and the ability to prove this depends on the courts being able to rely on the presumption of mental capacity in the absence of evidence to the contrary. It was also noted that there were many statutory exceptions to the “golden thread” rule.
43. The Court considered that, in analysing the permissibility of an onus cast upon the defence, it was important to start with the structure of the offence. It stated that, as a general principle, it would be more difficult to justify a provision that required the accused to prove (or, perhaps, disprove) a constituent element in the offence. If, however, what the defence was required to do was to establish a special defence or exception, then it would be less objectionable to impose a burden of proof. It was important to bear in mind that the presumption of innocence related to the actual offence charged.
44. On the issue of diminished responsibility, the Court ruled that s. 2 of the 1957 Act had not altered the ingredients of the offence of murder. The change brought about by it was the creation of a benefit to defendants who were in a position to take advantage of it. It was irrelevant whether it was treated as creating a defence to a charge of murder or as dealing with capacity to commit the offence. An accused who did not seek to rely on the section did not have to prove anything. The policy considerations said to justify the rule were the difficulty it would create for the prosecution if it had to prove a negative, and the fact that there was no obligation on the accused to submit to an appropriate examination.
45. Leave to appeal to the House of Lords was refused in Ali and Jordan, but granted in the third case, Lambert. That case concerned a charge of possession of a controlled substance with intent to supply. At issue was a provision similar to the Irish legislation under consideration in DPP v. Smyth Snr., discussed above, where it was for the appellant to “prove” that he neither knew nor suspected, nor had reason to suspect, that the bag he was carrying had contained a controlled drug. This had always been understood in English law as meaning proof on the balance of probabilities. In Lambert that burden was held by the Court of Appeal to be justifiable and proportionate having regard to public policy considerations.
46. In contrast, the majority of the House of Lords took the view that to read the section as imposing more than an evidential burden on the defence would amount to an infringement of the presumption of innocence. Of particular concern was the possibility that an accused could be convicted even in circumstances where the jury was not convinced of guilt, and might have thought that the defence offered was as likely as not to be true.
47. It should be noted that some strong observations were made on the dangers of paying too much attention to the structure of the legislative provisions. Lord Steyn was unimpressed by the distinction argued for (by the prosecution) between constituent elements of an offence and the establishment of a statutory defence. At pg 571 he said:
48. An effort to re-argue the issue in relation to the defence of diminished responsibility was made in the Court of Appeal in R. v. Foye  EWCA Crim 475. The facts of the case involved an extremely violent killing by a man who, all the expert witnesses agreed, had a severe dissocial, or psychopathic, personality disorder. There was thus no question as to whether or not he had an abnormality of mind and the issue in the case was whether his responsibility was “substantially impaired”. In the appeal against conviction the defendant contended inter alia that he should not have borne the burden of proving, on the balance of probabilities, that he was in a state of diminished responsibility at the relevant time.
“The distinction between constituent elements of the crime and defensive issues will sometimes be unprincipled and arbitrary. After all, it is sometimes simply a matter of which drafting technique is adopted: a true constituent element can be removed from the definition of the crime and cast as a defensive issue whereas any definition of an offence can be reformulated so as to include all possible defences within it. It is necessary to concentrate not on technicalities and niceties of language but rather on matters of substance.”
49. The Court of Appeal stated that no authority had cast any doubt on the correctness of its view in Ali and Jordan. It did not accept an argument that that view was inconsistent with the House of Lords decision in Lambert. However, rather than simply holding that it was bound by the earlier decision the Court went on to address the issue of principle.
50. The Court said that the “very clear justification” for s.2(2) of the Act of 1957 lay in the following factors.
51. The Court accepted that the Salabiaku test necessarily involved the proposition that the mere fact that the reverse onus was created by national legislation could not by itself mean that it was proportionate and justified, but it considered that it was “not without significance”. Two questions arose - the first was whether the subsection impinged on the presumption of innocence. If it did, the second was whether it was a proportionate and justified modification of that presumption. It was acknowledged that the two questions overlap, since the extent to which the onus relates to a component of an offence or to an exception of recognised excuse for it can be addressed at both stages.
“(i) Diminished responsibility is an exceptional defence available in an appropriate case with a view to avoiding the mandatory sentence which would otherwise apply, so that a discretionary sentence can be imposed, tailored to the circumstances of the individual case.
(ii) Diminished responsibility depends on the highly personal condition of the defendant himself, indeed on the internal functioning of his mental processes.
(iii) A wholly impractical position would arise if the Crown had to bear the onus of disproving diminished responsibility whenever it was raised on the evidence; that would lead not to a fair, but to a potentially unfair trial.”
52. It was also accepted that the distinction between a component of the offence and an exception or excuse could be difficult to discern, depending on the grammatical form adopted by the framers of the provision, and that in any event the distinction might not always provide an answer to the question whether the provision was justified. Nonetheless, the distinction remained relevant to the issue of justification because, as Kerr LCJ. had said in the Northern Ireland case of R. v. McQuade  NICA 2, it was clear that it was easier to justify a burden on a defendant claiming entitlement to a statutory defence than to support a requirement that a defendant discharge an onus of proof in relation to an element of the offence.
53. In any event, the Court considered that there was no difficulty about discerning the distinction in the case of diminished responsibility. Even if the defence of insanity were to be seen as going to mens rea, as it was by the Canadian Supreme Court in Chaulk, the same could not be said of diminished responsibility. The Scottish courts that developed it described it as an extenuating circumstance, with the effect of modifying the character of the crime, or as justifying a modification of the sentence, or both. The legislative provision did not require a defendant to disprove an element of the offence but to establish an exception or excuse, and had nothing to do with the requirement that the prosecution must prove an unlawful killing with the intention to kill or cause grievous bodily harm. The argument that the section created a risk that a defendant might be convicted by a jury that was less than sure of his guilt could not be sustained, since diminished responsibility did not arise at all until the jury was sure that he had carried out an unlawful killing with the requisite intent. In the Court’s view, there was no impact upon the presumption of innocence.
54. However, the Court of Appeal also considered the alternative assumption, that is, that there was an impact on the presumption of innocence. In that context, it took the view that diminished responsibility was closely analogous to insanity, rather than to defences which do not involve abnormality of the mind. The relevant connection was found in the fact that both involve a challenge to the assumption of normal mental functioning until the contrary is shown. In both cases it would as a matter of practicality be impossible for the prosecution to disprove beyond reasonable doubt an assertion that a defendant was insane or suffering from diminished responsibility. It would not be sufficient for the prosecution to invite a jury to reject poor evidence - it would have to go further and adduce evidence of the absence of abnormality. If the defendant refused to submit to medical examination, or refused to cooperate fully, or refused access to medical records, the prosecution task would be impossible.
55. In response to a submission that the section could be “read down” to provide for an evidential burden, the Court said that if operated in this manner the section could involve no more than raising the issue by some piece of evidence. It would be easy to do so, particularly since “abnormality” was not limited to an identifiable or diagnosable mental illness but could extend to any malfunctioning of the mind or personality. As an example, it was suggested that defence counsel could elicit the fact from prosecution witnesses that the accused had been behaving oddly.
The view of the Canadian Supreme Court - R. v. Chaulk  3 S.C.R. 1303
56. The Canadian Charter of Rights and Freedoms guarantees the right to be presumed innocent until proven guilty according to law. The statute dealing with insanity prohibits the conviction of a person in respect of an act or omission committed while that person was insane, but also provides that every person shall, “until the contrary is proved”, be presumed to be and to have been sane. Canadian courts had held since 1940 that where the issue of insanity was raised there was a burden on the accused to prove it on the balance of probabilities.
57. In Chaulk the appellants, whose defence of insanity in a murder trial had been unsuccessful, claimed that the presumption of sanity and the nature of the burden of proof thereby cast upon the accused was contrary to the Charter. It was argued inter alia that the phrase “until the contrary is proved” should be interpreted as requiring the accused merely to discharge an evidentiary burden - that is, to raise a reasonable doubt as to insanity. That contention was rejected as being contrary to the clear wording of the legislation, which was held to create a persuasive burden.
58. However, the majority also considered that the insanity provisions operated as an exemption from criminal liability, predicated on an incapacity for criminal intent, which depending on the facts would usually amount to either a denial of mens rea or an excuse for what would otherwise be a criminal offence. Since insanity can negative mens rea, the argument put forward by various State parties to the effect that the section only came into play after the prosecution had otherwise proved its case beyond reasonable doubt was rejected. Further, since sanity was an essential element in a finding of guilt, a conviction following a failed claim of insanity must be seen as following from the presumption of sanity and not merely from proof of the ingredients of the offence.
59. In those circumstances the Court found that the reverse onus did infringe the presumption of innocence. However, it went on to hold that the infringement was justifiable because without it the prosecution would be “encumbered with an unworkable burden”. The statutory provisions were described as an accommodation of three important societal interests - avoiding an impossible burden on the prosecution; convicting the guilty and acquitting those who truly lacked the capacity for criminal intent. The resulting compromise would not always produce the ideal result but this was the inevitable consequence of the state of scientific knowledge in the area. Alternative approaches would also raise problems under the Charter.
Discussion and conclusions
60. All of the authorities discussed here share certain fundamental assumptions. The presumption of innocence, whether construed in terms of the Constitution, common law or the European Convention, is a bedrock principle of our criminal justice system. The concomitant principle is that the prosecution must prove every element of a crime. However, the legislature may in some instances cast a burden on the defence in relation to a particular issue. In most cases, any such burden will extend only to the necessity to show the existence of a reasonable doubt. In other, limited instances there may be an onus to prove some matter on the balance of probabilities.
61. In determining whether the reverse burden under challenge amounts to an impermissible infringement of the presumption of innocence, the Court must firstly consider whether, properly interpreted, it does have that effect. If it does, the possibility may arise of interpreting or “reading down” the legislation to require only an evidentiary burden as in Lambert and in Smyth. One way of approaching the issue is to consider the elements of the offence and determine whether or not the defence is being required to rebut an element that would otherwise be for the prosecution to prove beyond reasonable doubt. I bear in mind the necessity for caution in carrying out such an exercise, for the reasons identified by Lord Steyn in Lambert. What matters is the substance rather than the drafting technique adopted in a particular instance.
62. Where a reverse burden of proof might amount to an infringement of the presumption of innocence, because it does indeed require the defence to negative an element in the offence, the question of justifiability arises. This was what occurred in R. v. Chaulk, on the basis that in a given case the defence of insanity could be aimed at negativing mens rea. However, the burden was held to be justified in the light of the practical considerations applicable to the defence of insanity.
63. In the instant case, it seems to me that there is no question but that the Oireachtas intended, by use of the word “establish”, and by requiring the court or jury to make a “finding”, to cast a burden of proof on the defence that goes beyond the raising of a reasonable doubt. Does that violate the presumption of innocence in the case of diminished responsibility, in a manner requiring the Court to either reinterpret the statutory burden or to consider whether the infringement can be justified?
64. In my view it does not. I agree in general with the proposition that any burden cast upon an accused that could result in conviction by a jury, despite a reasonable doubt as to an essential part of the offence, would be an unlawful violation of the presumption of innocence. (I would add to this general proposition a caveat in relation to insanity and mens rea, in that the issues raised in R. v. Chaulk do not appear to have been canvassed in this jurisdiction.) However, I do not consider that the possibility arises in the context under consideration. The successful raising of the defence of diminished responsibility does not depend on negation of any element of the prosecution case, nor on proving any essential aspect of the offence. The long-established elements of murder remain as they were, and are for the prosecution to prove beyond reasonable doubt. Evidence of a mental disorder sufficient to qualify under the Act does not in itself rebut either the common law presumption of sanity and responsibility for actions, or the statutory presumption that the accused person intended the natural and probable consequences of his or her actions. It creates a new, mitigatory defence that reduces the consequences of a proven offence. It is therefore incorrect to suggest that the imposition of a burden of proof could require an accused to prove either the actus reus or the mens rea, since these are matters that must be proven by the prosecution beyond reasonable doubt before the question of diminished responsibility can arise. Whether the necessary prosecution proof arises from admissions by the accused or from other evidence is irrelevant. For the same reason, it is not the case that a person could be convicted of murder by a jury that has doubts about his or her guilt. The context thus differs from Smyth, where a burden of proof to the standard of the balance of probabilities could indeed have had that result.
65. In the circumstances I consider that the provision in question does not affect the presumption of innocence.
66. However, I think that it is worth pointing out that the policy factors that justify the same onus of proof as in the case of insanity are also clear. The same difficulties that the prosecution would face in proving beyond reasonable doubt that an accused is sane would arise in an attempt to prove that the responsibility of the accused was not diminished by reason of mental disorder. If the prosecution bore such a burden it would have to prove this positively - inviting the jury to reject dubious evidence from the defence would not suffice. The problem stems from the intrinsically subjective nature of the defence; from the fact that mental disorders and their effects are not necessarily the subject of ordinary life experience or knowledge and will generally require some level of expert assistance to the jury or court; and from the fact that an accused cannot be compelled to participate in any form of medical examination by the prosecution. For those reasons the defence of insanity has always imposed a burden of proof on the accused. The same considerations arise with diminished responsibility.
67. In the circumstances the jury was correctly charged as to the onus of proof. I would therefore dismiss the appeal.