What key factor led to the change of charge in R V Byrne (1960) to manslaughter?

The change of charge in R v Byrne (1960) to manslaughter was primarily influenced by mitigating evidence of mental illness. In this case, the offender, Byrne, was suffering from a severe mental disorder at the time of the crime, which played a crucial role in understanding his state of mind and intentions. The court recognized that his mental illness significantly impaired his ability to exercise self-control and understand the nature of his actions, leading to the conclusion that he did not possess the intent necessary for a murder charge.

This evidential context surrounding Byrne's mental health was pivotal; it allowed for a re-evaluation of his culpability. Instead of finding him capable of expressing malicious intent to kill, the jury's awareness of his mental illness prompted a shift to manslaughter, reflecting a more nuanced understanding of criminal responsibility that considers mental state as a mitigating factor. This case illustrates how the legal system can accommodate complexities involving psychological factors in determining culpability.