Stop spreading misinformation.

In the UK the law on self-defence is established through a combination of common law (the law developed through court decisions) and statute. The law on self-defence allows a person to use reasonable force to defend themselves or another, to protect property, to prevent crime or to apprehend a criminal offender.

The common law gives guidance that violence used in self-defence must be exercised in accordance with the ‘rule of law’, and the ‘preservation of the Queen’s Peace.’ This essentially means that it can be used in the context of upholding a peaceful and law-abiding society. The relevant statutory laws are:

Criminal Damage Act 1971

Criminal Law Act 1967

Section 76 of the Criminal and Justice Act 2008

The CPS will not prosecute every case of violence used in self-defence because in some cases it might be accepted at an early stage by the police or prosecutor that the use of force was lawful. When making this consideration, the prosecutor will balance the public interest of promoting responsible citizen action towards maintaining law and order vs discouraging vigilantism and use of violence. Where the defence of self-defence is raised, in order to disprove it, the prosecution must prove beyond reasonable doubt that the violence was not carried out in self-defence.

In some circumstances, it could be lawful to stab someone in self-defence. Say an intruder enters your home, you are standing in the kitchen and you grab a knife that you use to defend yourself or your family member. This may be legal if the force used is considered to be reasonable in the circumstances as you honestly believed them to be.

This could be the case even if you killed the intruder.

If you had an honest but mistaken belief that the intruder was armed – for example if they reached inside their jacket and you thought that they were pulling out a weapon – then the force that you used in stabbing them could be taken to be reasonable. However, if for example you stabbed the intruder as they were attempting to flee your home, the court may be less likely to accept that you acted in self-defence.

Stabbing someone in response to a much less severe assault against you is unlikely to be lawful self-defence. If you are in a pub and someone punches you, stabbing them in turn would probably be considered to be grossly excessive. In those circumstances, you may still be liable for a criminal offence.

You are entitled to use force in order to protect yourself, your family, and your property against an immediate threat. You do not have to wait to be attacked first in order to use force to defend yourself, your family, or your property.

However, you must be acting reasonably and in good faith. CPS guidance suggests that if the householder is confronted by an intruder in their home, wherever possible they should call the police. The guidance recognises that it can be difficult in the heat of the moment to know what level of force is appropriate. You are not expected to make ‘fine judgments’ in this regard, and ‘so long as you only do what you honestly and instinctively believe is necessary in the heat of the moment, that would be the strongest evidence of you acting lawfully and in self defence.’ This applies even where you use something ‘to hand’ as a weapon. In some cases, force that has resulted in the intruder’s death has been found to be lawful self-defence. The force must be proportionate to the threat. This means that, for example, if the intruder is armed, a higher level of force will be permissible in self-defence.

If you use disproportionate force to protect yourself or another person, the law will give you the benefit of the doubt. However, disproportionate force to protect property could still be unlawful. Where the court finds that the force that you used was ‘grossly disproportionate’ or was enacted in revenge, this may go beyond what is considered acceptable self-defence.