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Self-defence, duress and necessity

Previous: Criminal incapacity

Self-defence, duress and necessity are all ‘proper’ defences to crimes. Once the actus reus and mens rea of an offence have been proven by the prosecution, if a defendant can prove one of the below defences, he will escape liability.


Section 76 of the Criminal Justice and Immigration Act (CRIMJIM) 2008 merges several common law defences: the use of reasonable force to prevent crime, common law self-defence and common law protection of property. Self-defence allows a defendant to be excused from liability where he uses reasonable force against another person where that act would normally constitute an offence. S 76(1) provides that the section is to be used in assessing whether the force was reasonable or not. When a jury assesses a self-defence, they must decide whether the force used by a defendant was objectively reasonable in the circumstances as they were believed by the defendant.

The basics

S 76(3) provides that reasonableness is to be assessed in the circumstances as the defendant (subjectively) believed them to be. This subsection is based on Beckford v R [1988], which found that if a defendant could avoid an offence of rape with an honest belief in consent, a police officer should also be able to get away with shooting an unarmed man with the honest belief that he was armed. However, DPP v Morgan [1975], the authority for subjective consent, has now been overruled by the Sexual Offences Act 2003. There is therefore a strong argument in favour of removing this subjective element of the defence.

  • R v Faraj [2007] – defendant was incorrectly required to have reasonable grounds for suspecting that a gas engineer was a burglar. This was correctly reversed on appeal to allow a subjective belief.
  • R v Oye [2013] – self-defence may not be used where the defendant is insane.

S 76(4) provides that it is for a jury to decide whether a defendant held the subjective belief upon which his defence is based.

S 76(6) then requires a jury to decide whether the force used by the defendant was objectively disproportionate. Or not. If not objectively disproportionate, the force will be classed as reasonable and the defendant will be acquitted.

  • R v Yaman [2012] – The force used by a shop owner of a gas engineer was disproportionate.
  • R v Owino [1996] – This case reversed R v Scareltt [1993], reversing a brief foray into an entirely subjective defence (both trigger and response).

S 76(5A), as a result of an outcry over householders being unable to repel intruders, will class force used against trespassers as reasonable as long as it is not objectively grossly disproportionate. Under s 76(8A), a householder is any non-trespasser using self-defence to repel a trespasser. One of the cases leading to this outcry was R v Martin (Anthony) [2002]. A local hero shot trespassers, injuring them using disproportionate force. A mental illness could not be used to assist in finding that force was reasonable in self-defence. This case also distinguished between two elements of subjective ‘trigger’ test in self-defence, finding that a subjective test should be used where the defendant makes a mistake of fact, but an object test should be used where a mistake is made as to the danger presented by those facts, two propositions which are very difficult to distinguish. The hero’s self-defence plea failed, but his sentence was reduced to 5 years on the grounds of diminished responsibility.

A duty to retreat?

Under s 76(6A), the possibility of a defendant retreating is to be considered. R v Julien [1969] suggested that a defendant should demonstrate his lack of want to fit, which may include physically disengaging. According to R v Bird [1975], that suggestion went to far, but a defendant’s disengagement was said to make later force seem more reasonable.

Pre-emptive strikes

According to Beckford v R [1988], circumstances may justify force to be used in self-defence prior to harm coming to the defendant.

  • Devlin v Armstrong [1971] – honest anticipation of an immediate attack may justify pre-emptive force, but not against a police officer during a protest
  • R v Mason (1756) – self-induced self-defence is not allowable
  • R v Rashford [2005] – starting a fight will not exclude self-defence if circumstances change
  • R v Keane [2010] – Starting a fight will not exclude self-defence unless it was the defendant’s purpose to incite violence

Other points to note

  • s 76(10)(b) allows a defendant to use self-defence to defend others. In R v Duffy [1967], the defendant defended his sister, but the relationship itself was irrelevant to the case.
  • Excessive force will not provide a defence to murder, according to R v Clegg [1995]. The defence of loss of self-control should be preferred.
  • R v Hitchens [2011] acknowledged that force used against against an innocent third party could be acceptable in certain circumstances. It would be more acceptable if a certain (more serious) crime was imminent.
  • In theory, self-defence permits murder if reasonable. This may be contravene the European Convention of Human Rights which says that the right to life should only be violated where necessary (a stricter test than reasonableness)

Duress by threats

As of the 14th century, duress has been recognised as absolving a defendant from liability where a more evil person than the defendant is responsible for a particular crime, by threatening the defendant in order to make him commit a crime which he would not otherwise commit. According to R v Hasan [2005], the defence is popular among terrorists, and according to Lady Hale, is easily raised and difficult to disprove. Lord Bingham would prefer sentencing discretion as opposed to a defendant being absolved from liability.

According to R v Graham [1982], where an intoxicated defendant helped strangulate his wife, there are two requirements in any duress claim:

  1. The defendant must have reasonably feared that he would be killed or have inflicted on him serious injury
  2. The jury must be sure that a sober person of reasonable firmness sharing the defendant’s characteristics would have acted in a similar way to the defendant

Fear of death or serious injury

  • R v Dao [2012] – a defendant could not use duress as a defence to being forced to work in a cannabis factory for fear of self-imprisonment
  • R v Baker [1997] – a fear of serious mental harm is not enough, the harm threatened must be physical
  • R v A [2012] – rape is classed as serious injury for the purposes of duress
  • R v Safi [2003] – there does not have to be an actual threat, just a reasonable belief in one, justifying the quashing of a conviction where the defendant had hijacked a plane
  • R v Martin (David) [2000] – As the ‘fear factor’ test is objective, Martin’s mental disorder leading to him carrying out two robberies did not assist in pleading the defence of duress. A subjective test was suggested, but could not be applied due to binding precedent.
  • R v Hasan [2005] – The objective ‘fear factor’ test should not be relaxed, there must be both an objective and subjective belief in death or serious injury

Reasonable firmness test

  • R v Graham [1982] – this case phrased the test as above – would a sober person of reasonable firmness, sharing the characteristics of the defendant, have acted in the same way? The question is which characteristics may be relevant?
  • R v Hurst [1995] – the unusual submissiveness of a wife did not constitute a defence to assisting with importing cocaine.
  • R v Bowen [1996] – low IQ is not a relevant characteristic, but age, sex, pregnant status, physical disabilities and recognised mental illnesses will might be.
  • R v Martin (David) [2000] – the Court of Appeal recognised the effectiveness of a judge having discretion as to which characteristics are relevant, but the case may be wrong in that it also advocated for a subjective fear factor test.
  • R v Hasan [2005] – lady Hale described herself as a reasonable, but comparatively weak grandmother

Other factors

On top of the main two factors for establishing duress, there are a number of additional factors which must be considered:

Target of threat

The target of the threat must be the defendant or someone who the defendant could reasonably regard himself as responsible for, according to R v Hasan [2005].

Specific crime

The crime seeking to be defendant must have been identified by the duressor, according to R v Cole [1994]. The defendant could not just carry out robberies to pay off debts in response to threats.


The threat must cause the offence, according to R v Valderrama-Vega [1985], although there may be other motives present.

Immediacy of harm

The threatened harm must be immediate. This used to be a relaxed requirement, as seen in R v Hudson and Taylor [1971], where two girls perjured themselves where their duressor was present in the courtroom where they were testifying. R v Hasan [2005] reaffirmed the strictness of this requirement, calling R v Hudson and Taylor [1971] “indulgent”. R v Rahman [2010] sought to clarify this requirement, distinguishing immediacy on the possibility of a defendant having a chance to seek protection.

Previous association

Duress may not be pleaded where a defendant was at fault in associating himself with his duressor. R v Baker and Ward [1999] found that where a defendant appreciated a type of future event which he may be compelled into as a result of his association, a plea of duress would fail. R v Hasan [2005] also tightened this requirement, finding that a previous association where the defendant knew or reasonably ought to know he might be compelled to do something in the future would destroy a plea of duress. Lady Hale dissented on this point, in the defence of ‘battered partners’. In R v Ali [2008], association was found where the defendant knew that his duressor habitually carried a knife with him.

No defence to murder/attempted murder

Finally, duress will not be a defence to murder or attempted murder:

  • DPP v Lynch [1975] – duress was allowed where the defendant drove IRA members to a murder scene
  • R v Howe [1987] – any participation in murder will exclude duress, as human life must be protected (the defendant injured the victim before another killed the victim)
  • R v Wilson [2007] – a father’s son successfully pleaded duress as a secondary party to murder
  • R v Gotts [1992] – the mens rea negating duress was shifted from the protection of human life to the intention to kill, as a “hair’s breath” from death should not allow a plea of duress. Intent to murder was also found to negate duress where a 16 year old defendant attempted to murder his mother. Lord Jaunty justified this by saying that an attempted murder intends something worse than an intended GBH which results in murder
  • R v Ness [2011] – conspiracy to commit murder was said in the Crown Court not to prevent duress from being raised

The Law Commission proposes that duress should be allowed as a defence to murder where a reasonable person in the position of the defendant would also have murdered the victim.

Duress of circumstances

Duress by threat requires there to be a specific threat. Duress of circumstances developed very quickly at the end of the 1980s, allowing circumstances to absolve a defendant from liability without a specific duressor.

  • R v Willer [1986] – reckless driving after passenger attacked, no defence as no specific crime directed
  • R v Conway [1988] – reckless driving after passenger attacked by plain clothes police officer, no defence, but Lord Woolfe required that, for a plea of duress of circumstances, circumstances must require an act to be done to avoid death or serious injury, constrained by the same requirements as duress by threat
  • R v Roger and Rose [1998] – no duress of circumstances in breaking out of prison to avoid committing suicide, as the threat was within the control of the defendant
  • R v Martin [1989] – a defendant failed the ‘reasonable firmness test’ in driving whilst disqualified to take his son to school under the threat of his wife’s suicide. There was evidence that other persons in the household could have legally driven the son to school, making the defendant’s behaviour unreasonable
  • R v Pommell [1995] – duress of circumstances applies to all offences except murder and attempted murder. A defendant illegally retained a firearm to prevent another person from committing an offence. A retrial was ordered where the defence was not properly left to the jury
  • R v Abdul-Hussain [1999] – immediacy was relaxed in this case, allowing a plane hijacking. It is likely that R v Hasan [2005] would likely reverse this case, just as it would have reversed R v Hudson and Taylor [1971] in the context of duress by threats
  • R v Quayle [2006] – no emergency when defendant took cannabis to relieve pain, so no duress of circumstances


In some cases, crimes have been held to be defensible on the basis that they were necessary. This (arguable) defence overlaps with duress of circumstances, if it exists at all. In Mouse’s Case (1608), throwing goods overboard could be considered necessary if it was done to save lives. Similarly, in Vantandillo (1815), it was permissible for a smallpox victim to walk to a doctor, even if risking spreading the disease in the process. R v Buckoke v GLC [1971] permits emergency vehicles to ignore red lights. Lord Denning takes the alternative view, but suggests that such a driver should not be prosecuted. In Southwark LBC v Williams [1971], Denning warned against the spread of necessity as a defence, stating that it could open an unclose-able door.

Medical necessity

It is accepted that necessity can be a defence for medical practitioners.

  • R v Bournewood Community and Mental Health NHS Trust [1998] permitted a doctor to detain a person on the grounds of mental health
  • R v Bourne [1939] found an abortion to be necessary (before abortion was legalised)
  • Gillick v West Norfolk and Wisbeck AHA [1986] allowed a doctor to necessarily prescribe contraception to a girl under the age of 16 without the doctor being classed as a party to any subsequent sexual act
  • F v West Berkshire AHA [1990] permitted the sterilisation of a patient without that patient’s consent

Statutory schemes

  • R v Quayle [2006] – no necessity defence in taking cannabis to treat pain
  • R v Shayler [2011] – no greater good necessity defence to breaking the official secrets act
  • R v CS [2012] – no defence to child abduction to prevent the non-imminent sexual violation of the victim

A defence to murder?

In R v Dudley and Stephens (1884), necessity was found not to provide a defence to murder where two shipwrecked sailors cannibalised their cabin boy in order to survive. As the sailors were suffering no wrong, they were not to inflict a wrong themselves. R v Howe [1987], in the context of duress by threat, is based on this case. In Re A (Conjoined Twins) [2001], it was obvious which sibling needed to be terminated by doctors, such that the other could survive. As there was no choice in who should die, and it was for the greater good, necessity worked in the favour of doctors murdering one of the conjoined twins in this case. 3 requirements were set out for finidng necessity:

  1. Was an act needed to avoid an inevitable and irreparable evil?
  2. Did the defendant do no more than was necessary?
  3. Was the evil inflicted proportionate to the evil avoided?

If each of these question can be answered in the affirmative, the necessity defence will be allowed.

The future of necessity

The future of necessity is uncertain. The Law Commission has proposed simply leaving judges to develop the defence where necessary.

Next: Criminal participation

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