Self-Defence CASES
In English law, self-defence (including defence of others and defence of property) permits the use of reasonable force to avert an imminent threat. In civil claims it operates as a complete defence to assault and battery if the defendant both needed to use force (as it reasonably appeared) and used a reasonable and proportionate degree of force. The doctrine overlaps with criminal law, but the civil test is applied by the court on the balance of probabilities.
Definition and principles
Two questions govern the analysis. Necessity: did the defendant honestly and reasonably believe that force was needed in the circumstances as they appeared? Proportionality: was the degree of force used no more than reasonably necessary to meet the threat? There is no absolute duty to retreat, but opportunities to withdraw or de-escalate inform what is reasonable. Pre-emptive action can be lawful where an attack is imminent. Mistaken belief may suffice if the mistake was reasonable; voluntary intoxication undermines reasonableness. The burden of proving self-defence in a civil claim lies on the defendant.
Common examples
- Public-facing roles: a security guard ejects a patron using only the force needed to achieve removal; gratuitous blows after control is gained are likely excessive.
- Citizen’s arrest / retail settings: holding a suspect for the police can be justified if necessary and proportionate; prolonged or painful restraint once the risk has passed is vulnerable.
- Home intrusion: confronting a burglar may justify robust force, but retaliatory or grossly disproportionate violence will defeat the defence.
- Defence of others: intervening to protect a colleague or bystander can be lawful if based on a reasonable appraisal of imminent harm.
- Defence of property: reasonable force to prevent theft or damage is permitted; force designed to punish or deter is not.
Legal implications
- Civil vs criminal: criminal law asks whether the force was reasonable in the circumstances as the defendant believed them to be; in civil claims the defendant must show both a reasonable belief in necessity and that the force used was objectively reasonable.
- Proportionality and evidence: the court examines timing, escalation, alternatives, injuries, training and policies. Body-worn video and CCTV are often decisive.
- Overlap with negligence: actions that are negligent or reckless are unlikely to be “reasonable force”. Where the defence fails, damages may still be reduced for contributory negligence by the claimant.
- Householder context: special statutory wording in criminal “householder” cases does not license grossly disproportionate force; civil claims remain governed by objective reasonableness.
Practical importance
For claimants, focus on whether the threat was imminent, when control was achieved, and whether force continued beyond that point. For defendants, record why force was thought necessary, what alternatives were considered, and how the level of force was controlled. Policies, training records and incident logs should match what happened on the ground.
See also: Assault and battery; False imprisonment; Necessity; Defence of property; Contributory negligence; Qualified privilege (reports); Public order powers.
Notes for students (key distinctions, with sources): in civil actions the defendant bears the burden and a mistaken belief must be reasonable; criminal law is more forgiving of honest but unreasonable mistakes, and “householder” wording affects criminal, not civil, analysis. See Ashley v Chief Constable of Sussex Police (HL) and commentary; Afriyie v Commissioner of Police (CA, 2024) on proportionality in civil claims; CJIA 2008 s.76 and “householder” materials; and Home Office/CPS guidance on reasonable force.
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A hunt saboteur, Mr Cross, was injured when a farmer, Mr Kirkby, struck him with a baseball bat during a confrontation. Mr Kirkby claimed self-defence. The court found Kirkby's actions were not grossly disproportionate, allowing the defence and clarifying principles of self-defence. Facts The claimant, Mr Cross, was a hunt saboteur who, with others, was attempting to disrupt the Longstone Edge Hunt. The defendant, Mr Kirkby, was a farmer and a member of the hunt staff. The saboteurs trespassed onto Mr Kirkby’s land. Mr Kirkby, holding a baseball bat, confronted Mr Cross and a fellow saboteur. An altercation ensued in
During peacekeeping operations in Kosovo, British soldiers opened fire on a car, injuring the claimants. Sued in tort, the Ministry of Defence argued self-defence. The High Court applied English law, finding the soldiers liable for trespass to the person as their belief of an imminent attack was unreasonable. Facts In 2001, in Pristina, Kosovo, a British Army patrol was involved in a public order incident. The claimants were passengers in a Volkswagen Golf which drove towards the soldiers. Believing they were under attack from the vehicle, three soldiers opened fire. One passenger, Mr Bici, was killed (his claim was settled
Following the fatal police shooting of James Ashley, his family pursued a civil claim for assault and battery, despite the police admitting negligence. The court ruled it was not an abuse of process to seek a verdict on the battery claim for vindication. Facts On 15 January 1998, during a police raid on his flat, Mr James Ashley was shot and killed by a police constable (‘PC Sherwood’). At the time, Mr Ashley was naked and unarmed. Mr Ashley’s father and son (‘the claimants’) brought a civil action against the Chief Constable of Sussex Police (‘the defendant’) for damages. The
