There are two basic categories of manslaughter; voluntary and involuntary. Voluntary manslaughter is where a person has an intent to kill, but their moral culpability is reduced because of provocation, substantial impairment of the mind, or because they acted in excessive self-defence. Involuntary manslaughter is where a person causes death while having no intent to kill or cause grievous bodily harm. Where the conduct causing death carried with it a sufficiently high risk of injury or death, despite the lack of intent the accused will be held accountable for the death. 

All are offences of the utmost seriousness and carry heavy gaol sentences if you are found guilty. It is important that you obtain legal advice as soon as you can so that a defence strategy can be put in place. Contact Hearn Legal 24 hours a day in order to arrange a free consultation.


A person charged with murder may be able to raise what is known as a ‘partial defence.’ If successful they will be found not guilty of murder but guilty of voluntary manslaughter. There are three partial defence as follow:

  • Extreme provocation

  • Substantial impairment of the mind

  • Excessive self-defence

Extreme provocation

If during a trial the accused is able to raise the issue of extreme provocation, it then falls to the prosecution to prove beyond reasonable doubt that the killing was not in response to extreme provocation. Broadly speaking the defence must establish the following:


  • The act was the result of a loss of control by the accused in response to conduct by the victim towards or affecting the accused; and

  • The conduct of the victim was such that it could have induced an ordinary person in the position of the accused to so far lose control so as to form an intent to kill or inflict grievous bodily harm

Substantial impairment of the mind

In order to raise the partial defence of substantial impairment an accused must show that it is more probable than not that at the time of committing the act causing death:


  • His or her capacity to understand events, or judge those actions as right or wrong or control him or herself, was substantially impaired by an abnormality of mind

  • That the abnormality of mind arose from an underlying condition

  • The impairment was so substantial so as to warrant liability for murder being reduced to manslaughter


This is a brief overview of a very complex area of law. In practice there are numerous other technical matters that must be proved.


Excessive self-defence

Self-defence arises where a person responds to a perceived threat with physical force. Where the accused believes the response to be necessary, and the force is found to be objectively proportionate to the threat, they will be found not guilty of any charge arising from the use of that force. However, where the force used is beyond what is proportionate it no longer provides an excuse.

Where a person is charged with murder, and the court finds that the act causing death was motivated by self-defence, but the force used was excessive, they will be found guilty of manslaughter in place of murder.

Maximum penalty: 25 years imprisonment


Criminal negligence

The concept of negligence has several meanings depending on the context in which it is being used. With regard to manslaughter it applies where the accused owes a duty of care to another person, and then because of a breach of that duty, the other person is killed. The conduct must be so gravely in error and carry with it such a high risk of serious injury that it deserves to be punished as a criminal offence. A relevant duty of care can arise in at least four situations:

  1. Where an obligation is imposed by law (such as when driving)

  2. Due to the nature of the relationship between two people (e.g. parent and child)

  3. Where a contract imposes a duty of care (e.g. employer and employee)

  4. Where a person has voluntarily assumed a duty towards another

In addition to proving the existence and breach of a duty, to be found guilty of this offence the prosecution needs to prove a number of complex additional matters. Upon conviction heavy gaol sentences can be imposed. A proper assessment of your options should be made in consultation with a highly experienced defence lawyer.


Maximum penalty: 25 years imprisonment



Unlawful and Dangerous Act

To be guilty of this kind of manslaughter the prosecution must prove amongst other things, that you engaged in an unlawful and dangerous act. Unlawful in this context does not include a breach of the traffic rules. For an act to be dangerous it must be established that a person in the position of the accused would have appreciated that the act was one which exposed another person to a risk of serious injury.

Maximum penalty: 25 years imprisonment