Correct on the date of publication - 2 March 2026
Question:
What are the defences against a charge of assault?
Answer:
Consent
It is possible for someone to consent to an assault on their person (such as tattooing or an operation, see below). A belief that consent had been given can be a defence, even if based on unreasonable grounds, provided that the belief is honestly held. Being reckless to whether consent has or has not been given (i.e. being aware an injury may occur and taking an unjustifiable risk of causing it) is not likely to be recognised as a valid defence by the courts.
For example:
- A salesman demonstrates a new flak jacket to the military using a volunteer soldier as a model. He is so keen to sell the product he stabs the jacket with a bayonet (knowing full well it is designed to stop shrapnel not knife attacks) and injures the soldier. He has assaulted the soldier.
- A salesman demonstrating a knife proof jacket to the police and causing injury to a volunteer because the jacket had an unknown defect, would not be guilty of assault.
Submitting to an assault is not consent. Similarly, consent is negated if given due to duress or fraud, but the burden of proof is on the prosecution to prove that this was how consent was obtained. Consent cannot be given by a child or young person if that person's understanding of what was involved meant that he/she did not understand the nature of the act. This is particularly relevant to body piercing (see below).
The absence of consent must be proved by the prosecution; this is best done with a statement from the victim, but could also be inferred from the circumstances if the victim was unable to give evidence, e.g. a very young child.
Consent cannot be given to an assault that inflicts bodily harm of a substantial nature (other than surgical operations and similar activities), see R v Donovan. A willing victim of sado-masochism cannot consent to being assaulted see R v Brown and Others for more, but a more flexible view can be taken to, for example, some body mutilation in limited and non-aggressive circumstances, see R v Wilson. Much depends on individual circumstances and on a case by case basis.
Implied consent
There are occasions when a police officer needs to draw attention to their presence in order to seek to ask questions or to warn or to advise a member of the public. A hand placed on a shoulder or arm could amount to an assault or battery, but it seems the courts are willing to accept that it is not an assault simply to tap on the shoulder or to take an arm. Of course, this could equally apply to any other member of the public acting in similar circumstances. These circumstances are of course distinct from arrest where reasonable force can be used.
The case of Collins v Wilcock involved a police officer taking hold of the arm of a person who was swearing and walking away from her when the police officer was attempting to speak with her. This case was considered again in McMillan v CPS where a woman was found drunk and abusive in a residential garden and was taken firmly by the arm and led from the garden to the street where she was arrested for being drunk and disorderly. See also the case of Winzar v Chief Constable of Kent for guidance on the issue of being physically 'placed' in a public place, for example if ejected from a restaurant, and then arrested for an offence that can only occur in a public place.
Surgery
In an emergency, surgery may be needed to save life (if it is not possible to obtain the consent of the patient due to their condition). In such a case, a surgeon, doctor or even a 'first-aider' performing what they honestly believe to be necessary surgery, even a 'roadside' procedure such as opening a blocked airway, would have a defence to what would technically be an assault.
A dentist who had been suspended from practising did not assault her patients by continuing to treat them (with their consent although they did not know about the suspension). The Court stated that consent would only have been negated by fraud if the patients had been deceived as to the nature of the treatment. They knew what treatment they were going to receive and consented to it (R v Richardson [1999] QB 444). A suspended medical professional is not in the same position as someone completely without training who would, at the very least, be 'reckless'.
Certain religions believe that surgical operations should not be carried out. If, even in an emergency, a patient with these beliefs is able to express their wishes coherently and refuse even life-saving treatment, that wish must be respected; consent has not been given and any surgery would be an assault.
Tattooing and body piercing juveniles
Although there is legislation prohibiting the tattooing of minors under the age of eighteen (Tattooing of Minors Act 1969), there is no specific legislation in respect of ear- piercing or body piercing of juveniles. People carrying out ear-piercing have to be registered under section 15 of the Local Government (Miscellaneous Provisions) Act 1982 but there are no age limits for the people whom they pierce, however most local councils impose some limits re the age. For example, some local councils only allow ear, nose and navel piercings in people over 18, people between 16 and 18 need to show proof of ID or an adult's consent and children under 16 must, by law, have a parent or guardian with them.
Lawful sports
This defence covers participation in all lawful sports which might result in injury due to their very nature, including boxing (under the Queensberry rules), soccer, rugby etc. Properly conducted sports are considered to be for the public good and therefore any assaults and batteries which take place during the course of the contest within the rules are lawful and the opposing players are taken to have given their consent to the injuries which they might suffer during the course of the match or contest. Such consent is even to the risk of potentially fatal injuries. Any injury caused by a player acting outside the rules of the sport will be an assault, and criminal proceedings should be considered.
See our Legal Q&A: Sporting activities - assaults and woundings
Reasonable chastisement - defence to common assault only
Following the enactment of section 58 of the Children Act 2004, a parent no longer has the legal right to inflict moderate and reasonable physical punishment on his or her children (reasonable chastisement). The position is the same for someone who is 'in loco parentis ', meaning 'in the place of a parent'. This can include a teacher, youth leader, baby sitter, etc.
Although this legal right has been removed, Parliament decided not to make such punishment by a parent an absolute offence. Instead, the issue would only arise in cases where there has been a charge of 'common assault' under section 39 of the Criminal Justice Act 1988. Only in this instance can the excuse of 'reasonable chastisement' be used as a defence to the charge. This defence cannot be used as a defence to sections 18, 20 or 47 of the Offences Against the Person Act 1861 (wounding and causing grievous bodily , occasioning actual bodily harm) or; an offence under section 1 of the Children and Young Persons Act 1933 (cruelty to persons under 16).
Self-defence
Self-defence can be a defence to any assault up to and including murder. The normal test a jury must use to decide whether a defendant was acting in self-defence or whether his/her actions were excessive, is laid down as follows:
'A jury must decide whether a defendant honestly believed that the circumstances were such as required him to use force to defend himself from an attack or threatened attack; the jury has then to decide whether the force used was reasonable in the circumstances ' (R v Owino [1996] 2 Cr App Rep 128).'
The force used must be reasonable in all the circumstances, and this is decided objectively by the jury/magistrates. Someone is entitled to use such force as is reasonable to protect himself, his family or his property. This principle includes using force to stop a police officer from making an unlawful arrest (in such circumstances the officer is assaulting the person defending him/herself). There is no longer any rule that someone must actively try to avoid a fight, but evidence that he started it could be used to negate a plea of self-defence.
See section 76 of the Criminal Justice and Immigration Act 2008, which expands on the common law and gives this defence a statutory footing.
Use of reasonable force in prevention of crime or in effecting or assisting an arrest
For a person who is not a constable, the use of reasonable force when making an arrest or in the prevention of crime, comes under section 3 of the Criminal Law Act 1967. For constables only see also section 117 of PACE.
View the full Legal Q&A document here, with links to related and similar legal questions.
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