Homicide offences - Voluntary manslaughter

Learning Outcomes

After reading this article, you will be able to explain the legal requirements for the partial defences of diminished responsibility, loss of control, and suicide pact in the context of voluntary manslaughter. You will understand how these defences reduce liability from murder to manslaughter, the relevant statutory provisions, the burden of proof, and how to apply these principles to SQE1-style scenarios.

SQE1 Syllabus

For SQE1, you are required to understand the law and practical application of voluntary manslaughter. In your revision, focus on:

• the statutory requirements for diminished responsibility, loss of control, and suicide pact
• the effect of these partial defences on a charge of murder
• the burden and standard of proof for each defence
• how to apply these defences to realistic client-based problems

Test Your Knowledge

Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, remember to look more closely at that area during your revision.

1. What are the four elements a defendant must prove to rely on diminished responsibility?
2. Name the two main qualifying triggers for loss of control under the Coroners and Justice Act 2009.
3. Who bears the burden of proof for the defence of suicide pact, and what standard applies?
4. Can voluntary intoxication alone amount to diminished responsibility?

Introduction

Voluntary manslaughter arises where a defendant has committed the actus reus and mens rea of murder, but their culpability is reduced by a partial defence. The law recognises three partial defences: diminished responsibility, loss of control, and suicide pact. If established, these defences reduce a conviction from murder to manslaughter, giving the judge discretion in sentencing.

Diminished Responsibility

Diminished responsibility is a statutory partial defence to murder, found in section 2 of the Homicide Act 1957 (as amended). It applies where a defendant was suffering from an abnormality of mental functioning that substantially impaired their responsibility for the killing.

Key Term: diminished responsibility
A partial defence to murder where the defendant proves they were suffering from an abnormality of mental functioning arising from a recognised medical condition, which substantially impaired their ability to understand their conduct, form a rational judgment, or exercise self-control, and which provides an explanation for the killing.

Legal Requirements

To rely on diminished responsibility, the defendant must prove:

1. They were suffering from an abnormality of mental functioning,
2. Arising from a recognised medical condition,
3. Which substantially impaired their ability to:
   • understand the nature of their conduct,
   • form a rational judgment, or
   • exercise self-control,
4. And the abnormality must provide an explanation for the defendant’s acts or omissions in the killing.

Key Term: abnormality of mental functioning
A state of mind so different from that of ordinary people that the reasonable person would consider it abnormal.

Key Term: recognised medical condition
A condition accepted by the medical profession, including mental disorders (e.g., schizophrenia, depression) and some physical conditions (e.g., epilepsy).

Key Term: substantial impairment
An important or significant reduction in the defendant’s ability to understand their conduct, form rational judgment, or exercise self-control—not merely trivial.

Key Term: provides an explanation
The abnormality must be a significant cause or factor in the defendant’s involvement in the killing.

Burden and Standard of Proof

The defendant bears the legal burden of proving diminished responsibility on the balance of probabilities (more likely than not). If not established, the defendant remains liable for murder.

Diminished Responsibility and Intoxication

Voluntary intoxication alone does not amount to diminished responsibility. However, if a recognised medical condition (such as alcohol dependency syndrome) is present, the jury must consider whether the abnormality, not the intoxication itself, substantially impaired the defendant’s responsibility.

Worked Example 1.1

A defendant with severe depression kills a neighbour after a period of delusional thinking. Medical evidence confirms the depression is a recognised medical condition. The jury finds that the depression substantially impaired the defendant’s ability to form rational judgment and was a significant factor in the killing.

Answer: The defendant may be convicted of manslaughter, not murder, if the jury is satisfied all elements of diminished responsibility are met.

Loss of Control

Loss of control is a statutory partial defence to murder, replacing the old law of provocation. It is governed by sections 54 and 55 of the Coroners and Justice Act 2009.

Key Term: loss of control
A partial defence to murder where the defendant’s acts or omissions resulted from a loss of self-control caused by a qualifying trigger, and a person of the defendant’s sex and age with normal tolerance and self-restraint might have reacted in the same or similar way.

Loss of Control: Legal Requirements

To rely on loss of control, the defendant must show:

1. Their acts or omissions resulted from a loss of self-control,
2. The loss of control had a qualifying trigger,
3. A person of the defendant’s sex and age, with a normal degree of tolerance and self-restraint, and in the same circumstances, might have reacted in the same or a similar way.

Qualifying Triggers

There are two main qualifying triggers:

• Fear of serious violence from the victim against the defendant or another identified person.
• Things said or done (or both) which constituted circumstances of an extremely grave character and caused the defendant to have a justifiable sense of being seriously wronged.

Key Term: qualifying trigger
A legally recognised reason for loss of control: either fear of serious violence or circumstances of an extremely grave character causing a justifiable sense of being seriously wronged.

Exclusions

• Sexual infidelity alone cannot be a qualifying trigger.
• The defence is not available if the defendant acted in a considered desire for revenge.
• The loss of control need not be sudden, but a delay may make the defence less likely to succeed.

Loss of Control: Burden and Standard of Proof

The defendant has an evidential burden to raise loss of control. The prosecution must then disprove the defence beyond reasonable doubt.

Worked Example 1.2

A woman, after years of domestic abuse, kills her partner during a violent argument. She feared serious violence and lost self-control. The jury is satisfied that a person of her sex and age with normal tolerance might have reacted similarly.

Answer: The woman may be convicted of manslaughter, not murder, if the jury accepts the loss of control defence.

Exam Warning

The loss of control defence is only available for murder. It cannot be used for attempted murder or any other offence.

Suicide Pact

A suicide pact is a statutory partial defence to murder under section 4 of the Homicide Act 1957. It applies where two or more people agree to die together, but one survives.

Key Term: suicide pact
An agreement between two or more persons to die together, whether or not each is to take their own life, in furtherance of the pact.

Suicide Pact: Legal Requirements

To rely on the suicide pact defence, the defendant must prove:

1. There was a genuine agreement to die together,
2. The defendant had a settled intention of dying in accordance with the pact,
3. The killing was done in pursuance of the pact.

Suicide Pact: Burden and Standard of Proof

The defendant bears the legal burden to prove the existence of a suicide pact and their settled intention to die, on the balance of probabilities.

Worked Example 1.3

Two friends agree to end their lives together. One survives and is charged with murder. Evidence shows a genuine agreement and a settled intention to die.

Answer: If the jury is satisfied, the defendant may be convicted of manslaughter, not murder.

Summary

Key Point Checklist

This article has covered the following key knowledge points:

• Voluntary manslaughter arises where a defendant has committed murder but a partial defence applies.
• The three partial defences are diminished responsibility, loss of control, and suicide pact.
• Diminished responsibility requires proof of an abnormality of mental functioning from a recognised medical condition, causing substantial impairment and providing an explanation for the killing.
• Loss of control requires a loss of self-control, a qualifying trigger, and that a person of normal tolerance might have reacted similarly.
• Suicide pact requires a genuine agreement to die together and a settled intention to die.
• The burden of proof for diminished responsibility and suicide pact is on the defendant (balance of probabilities); for loss of control, the prosecution must disprove the defence beyond reasonable doubt.
• If any partial defence is established, the conviction is reduced from murder to manslaughter.

Key Terms and Concepts

• diminished responsibility
• abnormality of mental functioning
• recognised medical condition
• substantial impairment
• provides an explanation
• loss of control
• qualifying trigger
• suicide pact