Reasonable force is the amount of force that the law allows a person to use in circumstances such as self-defence, defence of another person, prevention of crime, defence of property, or assisting a lawful arrest. In England and Wales, the phrase is closely linked with the Criminal Law Act 1967, the Criminal Justice and Immigration Act 2008, common law and case law.
The basic idea is practical rather than mechanical. A person under pressure is not expected to measure force with precision, but the response must still be connected to the threat and must not become revenge or punishment.
Legal Basis in England and Wales
Section 3 of the Criminal Law Act 1967 says that a person may use such force as is reasonable in the circumstances in the prevention of crime, or in effecting or assisting a lawful arrest.
Section 76 of the Criminal Justice and Immigration Act 2008 explains how courts should approach reasonable force in self-defence, defence of another, defence of property, prevention of crime and lawful arrest. It does not create a free-standing licence to use force. It sets out the approach to deciding whether the force used was reasonable.
The Crown Prosecution Service describes the broad position for householders as allowing reasonable force to protect themselves or others, prevent crime or protect property, while making clear that gratuitous or disproportionate violence can still be unlawful.
The Main Test
The court asks two connected questions:
- Did the person honestly believe that force was necessary?
- Was the amount of force used reasonable in the circumstances as that person believed them to be?
The belief does not have to be correct. A genuine mistake can still be relevant. However, the more unreasonable the claimed belief is, the less likely a court or jury may be to accept that it was genuinely held.
Necessity
Force must be used for a lawful purpose. Common lawful purposes include stopping an assault, protecting another person, preventing a theft, stopping property damage, or assisting a lawful arrest.
Force used after the danger has passed is much harder to justify. Chasing, punishing or continuing to strike someone who is no longer a threat may turn a defensive act into an assault.
Proportionality
The force used must be proportionate to the threat as it appeared at the time. A shove, grab or restraint may be reasonable in one situation. More serious force may be reasonable where there is a genuine threat of serious injury or death.
Proportionality does not require a perfect match. It recognises stress, fear, surprise and limited time to decide. It also recognises that serious violence can require a strong defensive response.
Self-Defence and Defence of Others
Self-defence covers force used to protect oneself from unlawful force. Defence of others covers force used to protect another person. The law can apply where someone intervenes because they honestly believe another person is being attacked, even if the situation later turns out to have been misunderstood.
The key issue is not whether the defender made the best possible decision with hindsight. The issue is whether the force was reasonable in the circumstances as they honestly believed them to be.
Prevention of Crime
Section 3 of the Criminal Law Act 1967 also covers force used to prevent crime. This can include stopping theft, criminal damage, assault or other offences.
For example, a shop worker may use reasonable force to stop a suspected thief leaving before police arrive if the legal conditions for a citizen's arrest are met. That does not allow unnecessary injury, humiliation or punishment.
Citizen's Arrest
Section 24A of the Police and Criminal Evidence Act 1984 allows a person other than a constable to arrest without warrant in defined circumstances involving indictable offences. In England and Wales this includes either-way offences such as theft.
Reasonable force may be used to carry out a lawful arrest, but the arrest itself must be lawful and necessary. If the arrest is unlawful, or the force is excessive, the person using force may face criminal or civil consequences.
Armed or Violent Attacks
A person facing an armed or violent attack may be entitled to use a higher level of force than would be reasonable in a minor confrontation. The law does not require someone who genuinely fears serious injury or death to wait passively until they are badly hurt.
The assessment still depends on the facts. Relevant factors can include the weapon, number of attackers, escape options, injuries, location, age, size, physical ability and whether the threat was continuing.
Household Cases
Householder cases are treated under a specific statutory approach. Force by a householder defending against an intruder is not automatically unlawful merely because it is disproportionate, but it is unlawful if it is grossly disproportionate.
This is a narrow rule for householder situations. It should not be confused with the ordinary test for force in public places or other settings.
Police Use of Force
Police officers also rely on legal powers to use force, including section 3 of the Criminal Law Act 1967, PACE powers, common law and human rights principles. Police force must be necessary, proportionate and accountable.
The College of Policing describes the legal framework for police use of force by reference to criminal law, human rights and policing powers. Serious uses of force can be reviewed through professional standards processes, the courts or independent investigation.
Practical Examples
Street Assault
A person is punched and pushed to the ground. They push the attacker away and run. That may be reasonable force because it is directed at escaping an immediate attack.
Continued Retaliation
The same person escapes, then returns several minutes later to hit the attacker. That later violence is much harder to justify because the immediate threat has ended.
Shop Theft
A shop owner sees a person conceal goods and head for the exit. Holding the suspect briefly until police arrive may be lawful if the offence and necessity requirements are met. Kicking or beating the suspect after they are restrained would not be justified by the theft.
Armed Attack
Someone is attacked by two people and believes they are at risk of serious injury. Strong defensive force may be reasonable if it is used to stop the attack or escape. The law looks at the situation as it appeared in the moment, not with calm hindsight.
See Also
References
Discussion log
Use comments for sourcing notes, corrections, and disputed details.
No comments yet.