Partial Defences

• What was the defence of provocation changed to and why?

  • Changed to a loss of self-control
  • “It is not designed to serve those who act in panic or fear" (McColgan, 2000)
  • R v Ahluwalia [1992]: She set her asleep husband on fire but she had suffered years of domestic violence and she had killed him out of defence of herself but she couldn’t rely on the defence of provocation as it was sudden
• What is the definition of loss of self-control?

  • S.54 of the Coroners and Justice Act 2009
  • Where a person (”D”) kills or is party to the killing of another victim, D is not to be convicted of murder if
  • D’s acts and omissions in doing so or being party to killing resulted from D’s loss of self-control,
  • The loss of self-control had a qualifying trigger, and
  • A person of D’s sex and age, with a normal degree of tolerance and self-restraint and in the circumstances of D, might have reacted in a similar way to D
• What is a qualifying trigger?

  • S.55 sets out what a qualifying trigger is
  • Fear of serious violence for the defendant or another - doesn't need to be an accurate fear but must be of serious violence and doesn't need to be targeted
  • Things said or done that either constituted circumstances of an extremely grave character or caused the defendant a justifiable sense of being seriously wronged
• What is a normal degree of tolerance and self-restraint?

  • An objective question decided by the jury
  • Also considers the history leading up to the event (accumulative provocation)
• Is the defence of a loss of self-control working as intended?

  • Data suggests that women were rarely able to invoke this defence in the past 13 years
  • It’s unclear if it has become less gendered and is likely unavailable to victims who’ve experienced emotional abuse but doesn’t fear violence (e.g., Sally Challen who had to rely on diminished responsibility instead)
• Diminished responsibility


  • Defined in s.2 (1) of the Homicide Act 1957, as amended by the Coroners and Justice Act 2009:
  • “A person who kills or is a party to the killing of another is not to be convicted of murder if D was suffering from an abnormality of mental functioning which
  • arose from a recognised medical condition
  • substantially impaired D’s ability to do one or more of the things mentioned in subsection (1A) and
  • provides an explanation for D’s acts and omissions in doing or being a party to the killing”
• What four elements are needed to establish diminished responsibility?

  • The D was suffering from an abnormality of mental functioning
  • The abnormality was caused by a recognised medical condition
  • Because of the abnormality of D’s ability to understand the nature of their conduct, form a rational judgment, or exercise self-control was substantially impaired
  • The abnormality explains D’s conduct, in that it was a significant contributory factor
• What is an abnormality of mental functioning?

  • Lack of ability to judge whether an act is right or wrong, control physical acts and exercise willpower
  • Must be present at the time of the killing
  • More than normal disturbances of everyday life
  • Relies on medical evidence and medical experts' assessment
  • For the jury to decide
• Recognised medical condition

  • Introduced by s52(1)(a) of CAJA in 2009
  • Abnormality of mental functioning must have arisen from a recognised medical condition
  • e.g., Depression, epilepsy, schizophrenia, “battered women syndrome”
  • Exceptions
  • Unhappiness, anger
  • Acute voluntary intoxication: Dowds [2012]
  • Compassion (mercy killing): Inglis [2010]
  • Developmental immaturity of a child
• R v Challen [2019]


  • Challen was convicted of the murder of her husband in 2011, after unsuccessfully trying to rely on diminished responsibility as a partial defence
  • After coercive control was criminalised by the Serious Crime Act 2015, she appealed successfully in 2019 relying on diminished responsibility due to several psychiatric conditions and the impact of experiencing coercive control
  • Clare Wade KC: “Set against this background, recent calls for a new defence which would apply in circumstances where certain offending is a direct consequence of domestic abuse, make good sense.”
• Is Diminished Responsibility working as intended?

  • Under pre-2009 law, DR was undisputed by the prosecution in 80% of cases
  • Relies heavily on medical expertise as it needs to be a ‘recognised medical condition’, should medical experts have that much sway over criminal law?
  • Could conflate moral, legal and medical issues as doctors will need to assess D’s sense of responsibility at the time of the offence
  • Because it involves an element of legal ‘compassion’ it is likely to create inconsistencies and some groups of D’s may be viewed more compassionately, e.g. ‘mercy killings’