Self-defence in English law

The common law defence of self-defence applies where the defendant uses necessary, reasonable and proportionate force to defend themselves or another from imminent attack. It is a complete defence to all non-sexual offences involving the unlawful use of force (anything from battery to murder). Because the defence results in a complete acquittal, the courts have interpreted the defence in a restrictive way so as to avoid acquitting too easily. For example, the courts will not usually acquit the defendant just because he thought the force used was reasonable – whether or not the force used was reasonable will be objectively assessed by the jury and not simply according to what the defendant thought at the time.

A defendant is entitled to use reasonable force to protect himself, others for whom he is responsible and his property. … It must be reasonable.

— Beckford v The Queen [1988] AC 130[3]

Lord Morris in Palmer v R[4] stated the following about someone confronted by an intruder or defending himself against attack:

If there has been an attack so that defence is reasonably necessary, it will be recognised that a person defending himself cannot weigh to a nicety the exact measure of his defensive action. If the jury thought that in a moment of unexpected anguish a person attacked had only done what he honestly and instinctively thought necessary that would be the most potent evidence that only reasonable defensive action had been taken…

— Palmer v R [1971] AC 814

Force is reasonable if a reasonable person would think it necessary to use force and would have used the same level of force as the defendant. This test is fundamentally objective: the defendant may not decide for himself what is reasonable based on his own values. However, the hypothetical reasonable person is imbued with the defendant's factual beliefs about the circumstances.[5] This is the case even if the defendant's beliefs about the circumstances are mistaken.[6]

Whether the force was reasonable is a question of fact for the jury. The jury may take into account all relevant circumstances of the case, including the level of threat (as the defendant believed it to be), the pressure of being under attack, the likely harm and the interests the defendant was protecting.[7] However, the jury may not rely on facts which the defendant was not aware of.[8] For example, if the defendant was unaware that the victim had a knife, the jury must ignore the fact that the victim was armed.

The classic test comes from the case of Palmer v The Queen, on appeal to the Privy Council in 1971:

The defence of self-defence is one which can be and will be readily understood by any jury. It is a straightforward conception. It involves no abstruse legal thought. … Only common sense is needed for its understanding. It is both good law and good sense that a man who is attacked may defend himself. It is both good law and good sense that he may do, but may only do, what is reasonably necessary. But everything will depend upon the particular facts and circumstances. … It may in some cases be only sensible and clearly possible to take some simple avoiding action. Some attacks may be serious and dangerous. Others may not be. If there is some relatively minor attack it would not be common sense to permit some action of retaliation which was wholly out of proportion to the necessities of the situation. If an attack is serious so that it puts someone in immediate peril then immediate defensive action may be necessary. If the moment is one of crisis for someone in imminent danger he may have [to] avert the danger by some instant reaction. If the attack is all over and no sort of peril remains then the employment of force may be by way of revenge or punishment or by way of paying off an old score or may be pure aggression. There may no longer be any link with a necessity of defence… If a jury thought that in a moment of unexpected anguish a person attacked had only done what he honestly and instinctively thought was necessary that would be most potent evidence that only reasonable defensive action had been taken.

— Palmer v The Queen [1971] AC 814, 832

The Legal Aid, Sentencing and Punishment of Offenders Act 2012 inserted a new section 76(6A) into the Criminal Justice and Immigration Act 2008. This provision clarifies that there is no duty to retreat, although an opportunity to retreat may still be taken into account when assessing whether the force was reasonable.

In R v Lindsay,[9] the defendant, who picked up a sword in self-defence when attacked in his home by three masked intruders armed with loaded handguns, killed one of them by slashing him repeatedly. The prosecution case was that, although he had initially acted in self-defence, he had then lost his self-control and demonstrated a clear intent to kill the armed intruder. The Court of Appeal confirmed an eight-year term of imprisonment.

In April 2013, the Crime and Courts Act 2013 further amended section 76. This amended the law to clarify that allow homeowners may still rely on self-defence in some cases where the force used is unreasonable, so long as it is was not grossly disproportionate.[6] This was further clarified by the High Court in January 2016.[10]

The modern law on belief is stated in R v Owino:

A person may use such force as is [objectively] reasonable in the circumstances as he [subjectively] believes them to be.

— R v Owino (1996) 2 Cr. App. R. 128 at 134[11]

If the defendant genuinely believes that an attack is imminent or underway, it does not matter that they were mistaken.

Preemptive self-defence is permissible in some cases. Lord Griffith said in Beckford v R:

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.

— R v Beckford (1988) 1 AC 130[12]

A defendant does not necessarily lose the right to claim self-defence merely because they instigated the confrontation. In some cases, a person who kills in the course of a quarrel or crime they started might still act in self-defence if the victim disproportionately escalates the violence. In Rashford,[13] the defendant sought out the victim, intending to attack him as revenge for an earlier dispute. The victim and his friends responded out of proportion to the defendant's aggression. At this point, the defendant had to switch from aggression to defence. The Court of Appeal held that the defendant will only lose the defence by being the aggressor throughout. The question is whether the defendant feared that he was in immediate danger from which he had no other means of escape, and if the violence he used was no more than appeared necessary to preserve his own life or protect himself from serious injury, he would be entitled to rely on self-defence. On the facts, the jury's decision to convict was not unsafe.

The rule that the defendant can rely on any honest belief is altered where the defendant has consumed alcohol or drugs. In R v Letenock,[14] the defendant claimed mistakenly to believe that the victim was about to attack him. The judge directed the jury that his drunkenness was irrelevant unless he was so drunk as to be incapable of knowing what he was doing. The Court of Criminal Appeal quashed his conviction for murder and substituted a verdict of manslaughter. Lord Reading CJ said at 224:

The only element of doubt in the case is whether there was anything which might have caused the applicant, in his drunken condition, to believe that he was going to be struck.

— R v Letenock (1917) 12 Cr. App. R. 221

This suggests that the question is whether there was any intelligible basis for the defendant’s belief. Hatton[15] held that a defendant who raised the issue of self-defence was not entitled to rely on a mistaken belief induced by voluntary intoxication, regardless of whether the defence was raised against a charge of murder or one of manslaughter. This applied the ratio decidendi in R v O' Grady[16] for murder and R v Majewski[17] for manslaughter. It follows that, if the defendant is voluntarily drunk and kills in what he mistakenly imagines to be self-defence because he imagines (as in Hatton) that the deceased was attacking him with a sword, he has no defence to a charge of murder; but if he claims to be so intoxicated that he is experiencing hallucinations and imagines that he is fighting giant snakes (as in Lipman)[18] then he can be guilty only of manslaughter.

The House of Commons Library compiled a list of people who have acted in self-defence as part of its briefing on the Criminal Law (Amendment) (Householder Protection) Bill 2005.[19]

Private citizens have a power to arrest any person for an indictable offence (Citizen's arrest) under s24A PACE1984 and the common law breach of the peace power to arrest. Where this power is lawfully exercised, the citizen may use reasonable force and other reasonable means to effect it. In R v Renouf,[24] the Court of Appeal ruled that s3(1) was available against a charge of reckless driving where the defendant had used his car to chase some people who had assaulted him and had manoeuvred his car to prevent their escape. Lawton LJ said:

This case has to be considered in the light of the evidence, which was said to have amounted to reckless driving. This evidence had two facets: one was what the prosecution alleged to be the acts of recklessness; and the other was that these same acts amounted to the use of reasonable force for the purpose of assisting in the lawful arrest of offenders.

— R v Renouf (1986) 2 AER 449

The right to use reasonable force to prevent crime comes from statute (S3 Criminal Law Act 1967. The definition of reasonable force is the same as the self-defence test. The definition of what constitutes a "crime" was clarified in R v Jones (Margaret)[2005] QB 259[25] as any domestic crime in England or Wales. Unlike self-defence, this defence also applies to the prevention of crimes which do not involve an attack on a person, such as defence of property.[26]

This is harder to get wrong as the test is whether:

• subjectively you honestly believed there was an imminent crime AND
• objectively you used reasonable force in the circumstances as you believed them to be

So there might only be a summary offence or no offence; you don’t have to tell them anything; you don’t have to wait for the police. But like arrest, it does have to be to prevent crime or escape. You don’t have to retreat[27] (although that is a factor in assessing reasonableness[28]), or wait for the first blow,[29] but must not take revenge. Revenge is evidence of unreasonableness[30] and seeking confrontation removes the defence.[31] No force might be reasonable if a threat would have sufficed.[32] A witness to violent crime with a continuing threat of violence may well be justified in using extreme force to remove a threat of further violence (CPS guidance). Physical characteristics can be relevant to reasonableness,[33] e.g. in a fist fight a man twice the size should take it easy or resist provocation. Injuries are relevant to reasonableness and public interest once unreasonableness has been found. CPS say that leeway should be given to those who have to confront in their job such as bouncers. It would be different if the court thought volunteers went out looking for confrontations. The CPS are told not to prosecute if the accused acted reasonably in preventing crime or apprehending offenders, but a factor is whether self defence was more vigilantism and violence than preserving law and order. They are supposed to allow leeway for excessive force that is not far from reasonable.

The CPS first have to check they can probably rebut self-defence beyond reasonable doubt, and even if they can then they have to check if prosecution is in the public interest. To prove assault despite a claim of self-defence CPS must prove beyond reasonable doubt that it was not defence of person or property or crime prevention or lawful arrest, or that force was excessive. Serious injury or use of weapons or ambush usually requires prosecution due to public interest if the force is unreasonable whereas minor injuries can suggest the public interest does not require prosecution. In case the CPS are dubious of your claim that force was reasonable, only using your bare hands, protecting the suspect from injury and only intervening in unexpected incidents rather than laying in wait are ways to try to prevent prosecution. CPS should be slow to prosecute where the public interest is affected by the complainant having been committing crime at the time; factors then include the damage or injury caused by the complainant and whether overzealous force was used to honestly uphold the law without revenge or vigilantism. CPS guidance is that violence is to be discouraged but responsible public spirited crime prevention is to be encouraged and they are to carefully balance the two.

You can use reasonable force to stop a likely breach of the peace, ie likely injury or damage to a witness's property (but not mere abuse or disturbance unless it makes you fear such injury or damage). This potentially gets around the problem that assault and threatening behaviour are summary offences. Breach of the peace is not a crime but is arrestable and can lead to binding over. Uniquely the power of arrest comes from a duty to prevent breach of the peace.[34] (There is a wider duty to preserve the public peace on request by the police,[35] failure without lawful excuse is indictable if able bodied). The courts accept that this is an ‘imperfect’ obligation so is no longer enforced. The risk of breach of the peace breaking out must be more than a real possibility but you are not expected to wait until crisis management is the only option. The police have more power as they can give a warning to cease disturbance then arrest for obstruction before breach of the peace is imminent. An example of a valid citizens arrest to prevent breach of the peace was where an off duty constable bundled a man off a bus who barged ahead of the queue at the bus stop which he feared would provoke an affray.