## Facts

- The defendant, Codere, appealed against a murder conviction.
- At trial, expert witnesses presented differing views on whether Codere could be certified insane.
- The appeal focused on whether Codere's mental state satisfied the insanity defense as defined by the M’Naghten rules.
- The defense argued that Codere’s actions indicated a lack of understanding of the act's wrongfulness.
- The prosecution contended Codere understood the nature of his act and its illegality.
- Evidence showed Codere was “abnormal mentally,” but the court examined whether this met the threshold for insanity under legal standards.

## Issues

1. Whether Codere’s mental condition at the time of the act fulfilled the requirements for the insanity defense under the M’Naghten rules.
2. Whether a lack of understanding of the “nature and quality” of the act, as interpreted by the court, should absolve criminal liability.
3. Whether awareness that the act was contrary to law precludes reliance on the insanity defense, even where mental abnormality is present.

## Decision

- The court clarified that “nature and quality” refers primarily to an understanding of the physical act and its legal wrongfulness, not merely its physical characteristics.
- It was determined that Codere understood both what he was physically doing and that his act was illegal.
- The court found the presence of mental abnormality alone insufficient for a successful insanity defense if the defendant understands the act's wrongfulness in law.
- Codere’s appeal was dismissed and his conviction upheld.

## Legal Principles

- For the insanity defense under the M’Naghten rules to succeed, a defendant must lack understanding of either the “nature and quality” of the act or that the act is wrong.
- “Nature and quality” was held to include knowledge that an act is contrary to law; mere mental abnormality, without such lack of knowledge, is not enough.
- Criminal responsibility is maintained if the accused understands both the physical aspects and legal implications of their actions, even when mentally abnormal.

## Conclusion

The court in R v Codere confirmed that the insanity defense requires a lack of awareness of an act’s physical nature or its illegality; mental abnormality alone does not absolve criminal liability where the defendant comprehends the wrongfulness of the act under the law.


R v Codere (1916) 12 Cr App R 21