R v O’Connor [1991]

1. Facts:

• D, while voluntarily intoxicated, head-butted V three times, killing him.

• Claimed he mistakenly believed he was acting in self-defence.

2. Outcome:

• Conviction for murder was substituted with manslaughter under diminished responsibility (DR).

3. Impact and Analysis:

• Mistaken Belief: Voluntary intoxication leading to a mistaken belief in self-defence does not negate culpability.

• Diminished Responsibility: Allowed for a reduction in charge to manslaughter when intoxication combined with other factors like mental disorders affects the defendant's state of mind.

• Legal Clarity: Highlighted how the law differentiates between voluntary intoxication alone and its combination with other impairing factors.