HomepageCommercial LawPrivate LawPublic Law & Human RightsCriminal LawEU & International LawCareers


Have Irlen Syndrome, or need different contrast? Click the button below for options.

Background Colours


Enter you email address below to subscribe to free customisable article notifications.

Alternatively, click the button below for our various RSS Feeds (available journal wide, or per section).

Self-Defence: More Complicated Than It Seems?

Article Cover Image

About The Author

Connor Griffith (Consulting Editor)

Connor is a law graduate from the University of Nottingham with a particular interest in intellectual property and corporate law. He is currently a trainee solicitor at a large national firm, sitting in the Real Estate department. Outside the law, he enjoys stand-up comedy and moaning about Brexit.

Legitimate use of violence can only be that which is required in self-defence.

Ron Paul

Self-defence is back in the public eye following the broadcasting of Channel 4’s recent one-off factual drama The Interrogation of Tony Martin. The show provided an insight into the police interrogation of farmer Anthony Martin in the case of R v Martin (Anthony) [2002] Crim LR 136, the facts of which proved to be the source of one of the most highly publicised and controversial cases towards the end of the millennium.

The complexity surrounding the concept of ‘self-defence’ in criminal courts is often underestimated. The general expectation that a defendant will be acquitted of a crime simply because they acted to protect themselves or someone else paints a deceptively simplistic picture of what is, in reality, a multi-faceted principle spread across a number of legislations and common law judgments. As such, what may be thought to be a self-explanatory defence is in fact, as described by Moore-Bick LJ in R v Hayes [2011] EWCA Crim 2680, a ‘notoriously difficult area of law’.

In light of The Interrogation of Tony Martin, this article will provide an insight into the specific requirements that must be proven for self-defence, attempting to clarify the multiple aspects of this deceptively difficult defence.

The Law: What Does Self-Defence Entail?

Courts around the world have long acknowledged the value of allowing citizens to protect themselves and others without facing punishment. As such, Lord Morris stated in R v Palmer [1971] AC 814:

It is both good law and good sense that a man who is attacked may defend himself.

The CPS guidelines state that a person may use such force as is reasonable in the circumstances for the purposes of:

  • Self-defence;
  • Defence of another;
  • Defence of property;
  • Prevention of crime; or
  • Lawful arrest.

The common law defence of self-defence (including defence of another) is heavily interlinked with the statutory defence of prevention of crime under Section 3(1) of the Criminal Law Act 1967. These defences have since been partially codified in Section 76 of the Criminal Justice and Immigration Act 2008 (CJIA 2008), which – per Section 76(9) – was ‘intended to clarify the operation’ of the pre-existing defences. Despite this, examination of the case law is still necessary to determine precisely how the defence works.

The law of self-defence was summarised succinctly in Smith and Hogan’s Criminal Law as follows:

The general principle is that the law allows such force to be used as is objectively reasonable in the circumstances as D genuinely believed them to be.

This is therefore a two-step defence, combining subjective and objective elements, for which the following questions must be considered:

  • What did D genuinely believe was happening when they acted in self-defence?
  • Was the force D used to defend themselves or another reasonable in the circumstances as D perceived them to be?

Genuine Belief

The court in Gladstone Williams (1984) 78 Cr App R 276 made it clear that the first limb of self-defence requires that D’s actions be judged on the facts as they believed them to be. This has been confirmed by Section 76(3) of the CJIA 2008.

This first limb is therefore a subjective test: it must be established exactly what D believed to be happening that required him to use self-defence. Provided D ‘genuinely believed’ that the circumstances were such as to require self-defence, it does not matter whether this belief was correct or mistaken.

Furthermore, it does not matter if D’s mistaken belief of the circumstances was completely unreasonable; instead, per Section 76(4)(a) of the CJIA 2008, the ‘reasonableness or otherwise of that belief is relevant to the question whether D genuinely held it’. However, as Section 76(5) of the CJIA 2008 confirms, D may not rely on any mistaken belief that was brought about by his voluntary intoxication.

The jury or magistrates do, however, provide a level of scrutiny: while D’s mistaken belief may be relied upon regardless of how reasonable it was, the court must still believe that D did in fact hold this belief. Nevertheless, this point does not constitute a sufficient audit of the circumstances for some; Jonathon Rogers, for example, argues that courts should conduct an in-depth examination of why D was mistaken before determining whether the defence should be applied.

Establishing What D Believed To Be Happening

Multiple rulings have been made regarding how the courts can decipher what D believed at the time of attack.

In R v Martin (Anthony) [2002] Crim LR 136 – the case on which The Interrogation of Tony Martin show was based – Martin shot and killed a burglar that was running away from his home. There was evidence before the Court of Appeal that Martin’s personality disorder made him perceive an exaggerated threat to his personal safety. However, Lord Woolf CJ asserted that, while a jury could take into account a defendant’s physical characteristics, they may not take into account a defendant's psychiatric condition 'except in exceptional circumstances which would make the evidence especially probative'.

As such, while D’s broken leg or old age may be valid in assessing D’s perceived vulnerability, it is unlikely that the court may take into account D’s mental conditions, such as Martin’s paranoid personality disorder.

This may seem unfair; in an age where more awareness is being given to mental disabilities, why are courts often willing to take into account D’s physical condition but not his mental condition? This concern is exacerbated through the fact that the need to assess the mental state of D is brought to the forefront of proceedings through the second limb of the test for self-defence relying on what D himself believed to be happening, thereby binding the relevance of mental state and the defence as a whole.

The argument can be made that if D does in fact perceive a greater threat than actually exists due to a mental condition, the defence of diminished responsibility will be available in instances where the victim is killed, or in very rare and extreme cases, a potential defence of insanity. Whether this is satisfactory, however, is debatable: self-defence results in a full acquittal, whereas diminished responsibility merely reduces the conviction from murder to manslaughter, and insanity may result in the institutionalisation of D.

Reasonable Force

The second limb of the defence is an objective test: the prosecution must demonstrate that the force used by D was not reasonable in the circumstances as D supposed them to be. Section 76(6) of the CJIA 2008, as supported in R v Yaman [2012], states:

[T]he degree of force used by D is not to be regarded as having been reasonable in the circumstances as D believed them to be if it was disproportionate in those circumstances.

Section 76(7) of the CJIA 2008 states a court may take the following into account (as well as other unlisted factors) when considering whether the force used by D was reasonable:

  • that a person acting for a legitimate purpose may not be able to weigh to a nicety the exact measure of any necessary action; and
  • that evidence of a person’s having only done what the person honestly and instinctively thought was necessary for a legitimate purpose constitutes strong evidence that only reasonable action was taken by that person for that purpose.

The first factor, under Section 76(7)(a) of the CJIA 2008, almost identically mirrors the statement made by Lord Morris in Palmer v R [1971] 1 All ER 1077. This principle ensures that the courts will not punish D for applying slightly more force than was necessary in the circumstances, provided D did what he honestly and instinctively thought was necessary.

However, if D goes too far beyond what is reasonable, and reacts disproportionately in the circumstances as he perceived them to be, the defence will fail and D may be convicted.

Arguably, this is particularly harsh in circumstances where D misreads the requirement for the use of lethal force, as the failure of the requirements of self-defence would likely result in a conviction of murder (or, at least, manslaughter). This occurred in R v Clegg [1995]; in which a Northern Irish soldier fired several shots at a car that did not stop at a checkpoint. Three out of the four shots fired were lawful, but the fourth shot – which killed V – was unlawful as it was fired once the car had already driven past Clegg, and therefore no longer posed a threat. As a result, even though Clegg believed himself to be acting in self-defence, his actions were excessive and he was consequently convicted of murder.

Pre-Emptive Strikes

The law provides that D may protect himself from an impending attack with the use of a pre-emptive strike if it is reasonably necessary. This is evident from Lord Griffiths’ statement in Beckford v R [1988] that:

[A] man about to be attacked does not have to wait for his assailant to strike the first blow or fire the first shot – circumstances may justify a pre-emptive strike.

However, it was also noted in Devlin v Armstrong [1971] NI 13 that the ‘anticipated attack must be imminent’; D cannot lawfully strike out at someone that they feel may simply attack them in the distant future.

Provoked Attacks

Perhaps controversially, the law also provides that D may rely on self-defence where he started off as the aggressor but then must protect himself from the retaliation of the victim. For example, D kicks V in the leg. While this initial kick will have been an unlawful assault, D may lawfully defend himself if V then pulls a knife on D in retaliation.

Self-defence is not applicable, however, where D deliberately aggravated V in order to be allowed to then lawfully attack him further ‘in defence’, per Lowry LCJ in R v Browne [1973] NI 96.

Difficulties lie, as ever, in deciphering between those cases in which D did not expect to have to defend himself from attacks (or from attacks at the level brought by V), and those in which D had deliberately provoked the anger of V in order to permit further attacks from D. As such, the availability of this defence is very dependent on all the circumstances in each case.

A Duty to Retreat?

Previously, the law required that D, per R v Julien [1969] 2 All ER 856, demonstrate:

… by his actions that he does not want to fight. He must demonstrate that he is prepared to temporise and disengage, and perhaps to make some physical withdrawal.

However, the court in R v Bird [1985] 2 All ER 513 later acknowledged that this placed ‘too great an obligation on a defendant’. As a result, the Legal Aid, Sentencing and Punishment of Offenders Act 2012 inserted Section 76(6A) into the CJIA 2008, which states:

In deciding the question [whether the degree of force is reasonable], a possibility that D could have retreated is to be considered (so far as relevant) as a factor to be taken into account, rather than as giving rise to a duty to retreat.

In other words, there is no longer a duty for D to try to retreat before defending himself – quite rightly, too, as to require an escape attempt could easily result in D suffering greater harm than if he were to protect himself instantaneously. However, while a failure to retreat will not remove D’s ability to claim he acted in self-defence, it could still go towards painting D’s actions as more ‘aggressive’ than ‘protective’; as such, courts have been given the opportunity to dive further into specific circumstances of each case, rather than following strict blanket rules.

Householder Cases

Additional thought must be given to cases in which D is protecting themselves or another in their own home; it is not concerned with the defence of property. Regarding these so-called ‘householder cases’ (defined in Section 76(8A) of the CJIA 2008), Section 76(5A) of the of the CJIA 2008 – inserted by Section 43 of the Crime and Courts Act 2013 – states:

In a householder case, the degree of force used by D is not regarded as having been reasonable in the circumstances as D believed them to be if it was grossly disproportionate in those circumstances.

The purpose behind the introduction of this section was made clear in the following statement by the then Minister for Policing and Criminal Justice, Damian Green MP:

The provision is not [a vigilantes charter], but a recognition that people confronted by a burglar and acting in fear of their safety in the heat of the moment cannot be expected to weigh up exactly how much force is required. In such extreme circumstances, we think that they should have greater legal protection.

Ormerod and Laird are sceptical, however, of whether this addition actually makes a difference, noting that the law already allows flexibility surrounding the amount of force used in the heat of the moment. Indeed, while an act of self-defence will be unreasonable in householder cases where it was ‘grossly disproportionate’ – compared to just ‘disproportionate’ in ordinary cases – it is easy to imagine that what may constitute ‘disproportionate’ to one jury could be ‘grossly disproportionate’ to another.


As demonstrated above, the law of self-defence is not quite as simple as one might assume. The defence is hardly a simple statement that when attacked you can do anything and everything to defend yourself and be exonerated by the courts.

The CPS guidelines state that, when reviewing cases involving assertions of self-defence, prosecutors must be aware of the balance to be struck between:

  • the public interest in promoting a responsible contribution on the part of citizens in preserving law and order; and
  • discouraging vigilantism and the use of violence generally.

This, ultimately, embodies the philosophy behind permitting the availability of this defence – citizens must be able to defend themselves from attackers, but cannot be afforded such immunity that they are then able to abuse this system so as to allow them to become the attackers.

For the latest articles straight to your inbox, you can subscribe for free. Alternatively, follow @KeepCalmTalkLaw on Twitter or Like us on Facebook.

Tagged: Criminal Law

Comment / Show Comments (0)

You May Also Be Interested In...

Deferred Prosecutions: Deferring Justice

10th Mar 2016 by Brent Esler (Guest Author)

Restructuring the Offence of Rape: A Strive to Meet Feminist Concerns

29th Dec 2015 by Jack Slone

Triggering Debate: The Legal Position of a ‘Shoot To Kill’ Policy

22nd Dec 2015 by Keir Baker

Joint Enterprise: The “Let Him Have It” Principle

25th Nov 2015 by Amy Ling

Gendered Legislation: Critiquing the Sexual Offences Act 2003

9th Nov 2015 by Bronte Cook (Guest Author)

Could Current ASBO Reforms Create a New Brand of Criminal?

14th Nov 2013 by Jessica Johnson

Section Pick October

Prosecuting Rape: Is the CPS Raising the Bar Too High?

Editors' Pick Image

View More


Keep Calm Talk Law: Moving Forward

3rd Sep 2019

Changing of the Guard: Moving Keep Calm Talk Law Forward

12th Aug 2018

An Anniversary or Two: Four Years of Keep Calm Talk Law

11th Nov 2017

Rising from the Ashes: The Return of Keep Calm Talk Law

18th Nov 2016

Two Years On, Keep Calm Talk Law’s Legacy is Expanding

11th Nov 2015


Javascript must be enabled for the Twitter plugin to function. Click below to visit us on Twitter.

Free Email Subscription

Subscribe to Keep Calm Talk Law for email updates, and/or weekly roundups. You can tailor your subscription on activation. Both fields are required.

Your occupation / Career stage is used to tailor your subscription and for readership monitoring.

Uncheck this box if you do not want to receive our monthly newsletter.

By clicking the Subscribe button, you agree to our privacy policy and terms of service. Please ensure you read these in full.

Free Subscription