A guide to the law and self defence

Individual Self-Defence in the UK

If an individual inflicts physical force or violence onto another that is considered unlawful and the individual could be prosecuted.   However, there are certain exceptions to this where the use of restricted force would be expected.  An example would be force inflicted in team sports, or a doctor on his patient.    

In addition UK law safeguards the right of any individual to use force for protection.  Where they have no other option, the use of force and violence, to a certain degree, is permitted, rendering lawful what would otherwise be illegal.  Using self-defence for protection can be justified in court even if the subject of the violence is seriously injured or even dies. 

Regulation of circumstances under which violence can be used in self-defence.

When can self-defence be used?

UK Common law dictates that force or violence may be used by an individual to defend himself or someone else from attack, or to defend their property.   Furthermore, section 3 (1) of the Criminal Law Act 1967 dictates that:

  • “A person may use such force as is reasonable in the circumstances in the prevention of crime, or in effecting or assisting in the lawful arrest of offenders or suspected offenders or of persons unlawfully at large.”

It is also permitted for an individual to act pre-emptively, before the crime is carried out if they genuinely believed it was the only available option of protection.  The best evidence of showing that force was the last resort and was absolutely necessary would be to show an initial retreat or withdrawal from the situation.  However this is not necessary in order to claim self-defence.

The law is clear that if the court believes that the individual provoked an attack or disturbance in order to use force and rely on the claim of self-defence, this claim will be dismissed. 

If an individual honestly believed that force was necessary at the time it was inflicted, but in hindsight it was clear that it was not, the claim of self-defence will still be applicable.  The Criminal Justice and Immigration Act 2008, Section 76 (7) states that 

  • “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”

Decisions are left to the discretion of the court that is required to understand that in the heat of anguish and fear perspectives on proportionality may not always be realistic.

Furthermore, an individual’s mental and physical situation must be taken into consideration.  A court can justify self-defence when someone with a physical or mental disability may perceive a greater threat than what exists, or may have experienced heightened fear of the consequences of a potential attack.

How can self-defence be used?

The most significant criteria when using self-defence is that only ‘reasonable’ and proportionate force may be used.   The individual should only use enough force necessary for protection and to stop the crime. 

If a court is led to believe that excessive force was used the individual stands at risk of being prosecuted.  If however someone is killed in a self-defence attack where excessive force was used, the conviction will be reduced from murder to manslaughter.

No weapon is allowed to be used, unless it is believed to be an everyday object such as keys or a shoe.  


  • Some people believe that the law does not go far enough in giving people the power to protect themselves. There have been several high-profile cases where individuals have been jailed after being accused of using excessive force against someone.  Some believe this criminalises the victim and allows the criminal to be victimised.  However, judgements must follow the principle ex turpi causa non oritur action: “from a dishonourable cause an action does not arise.” 

  • Another controversial issue is the ambiguity of the term ‘reasonable.’ Many argue that it is completely unrealistic to expect an individual under attack to act in a reasonable and proportionate way; natural human instincts will encourage any behaviour to protect.

Article written by...
Lucy Trevelyan LLB
Lucy Trevelyan LLB

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Lucy graduated in law from the University of Greenwich, and is also an NCTJ trained journalist. A legal writer and editor with over 20 years' experience writing about the law.