W2L5 Actus Reus, Defences, and Criminal Omissions

Vocabulary practice flashcards covering criminal liability, actus reus, mens rea, the role of defences, criminal omissions, and duty to act categories under Scots and English criminal law.

Actus Non Facit Reum, Nisi Mens Sit Rea

A Latin legal maxim stating that the act itself does not constitute guilt unless done with a guilty mind.

Actus Reus

The conduct, omission, or state of affairs prohibited by a particular criminal offence, as well as the consequences of those acts or omissions.

Mens Rea

The blameworthy state of mind that the accused must be proved to have possessed at the time of the prohibited conduct or during the existence of the prohibited state of affairs.

Constituent Elements of Criminal Liability

The foundational components required to establish criminal liability: Actus reus + Mens rea + Absence of a defence.

Absence of a Defence

The principle that criminal liability requires no recognised defence to exist; even if both actus reus and mens rea are present, an accused is not criminally liable if a valid defence (such as self-defence) applies.

Miller [1983] 2 AC 161

A case in which Lord Diplock criticised the Latin terminology of criminal law, stating it would aid analytical clarity to avoid 'bad Latin' and speak directly of the conduct of the accused and their state of mind.

Drury v H.M. Advocate, 2001 S.C.C.R. 583

A Scottish murder case where the accused killed his girlfriend with a hammer; the conviction was quashed and a retrial granted because the jury was misdirected regarding provocation and whether the accused possessed the required mens rea of 'wicked intention to kill'.

Galbraith v H.M. Advocate, 2001 S.C.C.R. 551

A Scottish appeal case concerning a woman convicted of murdering her husband, in which a retrial was granted due to the trial judge's misdirection regarding the defence of diminished responsibility.

Result Crimes

Offences where the criminal liability and definition of the crime depend on the specific harm or consequence caused by the conduct.

Hogg v McPherson 1928 J.C. 15

A Scottish case illustrating result crimes, where claims for accident damage failed because the accused was found not negligent and not responsible for the harm, meaning no crime was committed.

Criminal Omission

A statutory or legal offence consisting of a failure to perform a required act, where the criminal law penalises the failure of conduct itself rather than the resulting consequences.

Crime of Commission by Omission

An offence distinguished from pure conduct omissions by the fact that the failure to act replaces positive conduct, and criminal liability attaches because of the harmful result caused by that failure.

R v. Gibbins and Proctor (1919) 13 Cr. App. R. 134

A case establishing murder liability by omission where a father and his partner starved a child to death, based on the father's parental duty of care and the partner's implied, assumed duty of care.

Bone v HMA 2006 SLT 164

A Scottish case where a mother's conviction for culpable homicide for failing to intervene while her partner killed her child was quashed, because her physical and psychological condition reduced her parental responsibility.

R v. Russell 1933 VLR 59

A Supreme Court of Victoria decision where a husband who failed to rescue his drowning wife (while rescuing their children) was convicted of manslaughter based on an ongoing marital duty of care, despite their separation.

R v Stone and Dobinson [1977] 2 All ER 341

An English case finding siblings liable for manslaughter by omission after an infirm sister came to stay and died of neglect, establishing that voluntary assumption of care creates a legal duty to protect health and welfare.

R v Charlotte Smith 169 E.R. 1533 (1865)

A case holding that a lodging house keeper was not criminally liable for the starvation of a servant, because an adult of free will choosing to stay in poor conditions does not create a criminal duty of care on the employer.

R v Instan [1893] 1 Q.B. 450

A case finding a niece guilty of manslaughter by omission when she lived with and was supported by her ill, elderly aunt but failed to feed her or summon medical help, having voluntarily adopted a legal duty of care.

Bonar and Hogg v MacLeod 1983 S.C.C.R. 161

A Scottish case establishing that a police officer who breaches their public duty by standing by while a junior officer assaults a prisoner, and further assists by fast-marching the prisoner, is criminally liable.

MacPhail v Clark 1982 S.C.C.R. 395

A Scottish case establishing that an individual who creates a danger (a farmer burning straw near a dual carriageway that caused smoke and a car crash) has a legal duty to act reasonably to avert or remove that danger.

Paterson v Lees 1999 S.C.C.R. 231

A Scottish case highlighting the limits of omission liability, holding that a babysitter who allowed children to watch an indecent video breached a moral rather than a common law criminal duty, as expanding parental duties is a task for Parliament.

R v Smith 1979 Crim L.R. 251

A case illustrating the discharge of a duty of care, where a husband was acquitted of manslaughter after his wife, possessing rational decision-making capacity despite medical phobia, explicitly refused medical aid after a stillbirth.