Arguably consent is not a defence as consent means there has been no unlawful act. The relevant considerations are in what circumstances a person is able to give consent and whether genuine consent is given.
Consent can only become a factor when considering certain offences. Generally, if an injury is caused then consent is not a defence.
Consent is always a defence to assault or battery because there is no injury. The law will not interfere with people’s rights to do what they wish.
A person cannot consent to being killed. This raises important issues in relation to euthanasia and decisions to turn off a life support machine.
Life prolonging treatment
Airdale NHS Trust v Bland 
Mr Bland was severely injured at the Hillsborough disaster and was unconscious and in a vegetative state. He continued to breathe by himself and his digestive system still functioned. However, he could not communicate, was incapable of voluntary movement and had no sensory abilities. Doctors agreed there was no hope for recovery or improvement in his condition. After three years doctors and his family applied to the court for a decision on whether it was lawful to stop his artificial hydration and nutrition, which would lead to his death.
House of Lords decided that his treatment could be stopped. They made a number of findings in coming to this conclusion. Namely, artificial nutrition and hydration is a form of medical treatment and there is no distinction between withholding treatment (an omission) and discontinuing treatment.
Also, in order to make such a decision, it should be considered whether it is in the best interests of the patient that his life should be prolonged. This assessment should include the previous stated wishes of the patient and views of close relatives.
.. the law draws a crucial distinction between cases in which a doctor decides not to provide, or to continue to provide, for his patient treatment or care which could or might prolong his life, and those in which he decides, for example by administering a lethal drug, actively to bring his patient's life to an end.. the former may be lawful, either because the doctor is giving effect to his patient's wishes . . . or even in certain circumstances in which.. the patient is incapacitated from stating whether or not he gives his consent. But it is not lawful for a doctor to administer a drug to his patient to bring about his death, even though that course is prompted by a humanitarian desire to end his suffering, however great that suffering may be.. So to act is to cross the Rubicon which runs between on the one hand the care of the living patient and on the other hand euthanasia....
W v M and S and NHS PCT (2011)
Patient, a 52-year-old woman, known only as M, is suffering from a condition known as a
minimally conscious state. In a case before the Court of Protection, her family argued that she was in pain and her life support should be withdrawn and were opposed by the Official Solicitor and health authority in charge of the patient’s care.
A High Court judge ruled that the life sustaining treatment could not be stopped, stating:
.. The factor which does carry substantial weight, in my judgment, is the preservation of life. Although not an absolute rule, the law regards the preservation of life as a fundamental principle....
Dianne Pretty was paralysed by motor neurone disease. Her condition worsened which made it impossible for her to move or communicate easily even though her mental faculties remained. She wanted to be able to choose the time of her own death and would need her husband’s help. She took a case to try and ensure if he assisted in her suicide he would not be prosecuted. She argued that Article 2 of the European Convention on Human Rights protects the right to life and right to choose manner of death.
The House of Lords and European Court of Human Rights, both found that Article 2 did not provide the right to die. The courts found the protection of vulnerable citizens was of paramount importance. Diane Pretty’s case failed.
R (on application of Purdy) v DPP (2009)
Mrs Purdy, suffered from multiple sclerosis and declared her wish to travel to a country where assisted suicide was lawful to end her life when her illness became utterly unbearable. She sought information in order to make an informed decision about whether to ask her husband to help her travel.
Under S2 of Prosecution of Offences Act 1985, the DPP is obliged to give guidance to prosecutors on general principles to be used in deciding whether to prosecute in cases involving aiding suicide. The guidance gave little indication about issues relevant to those assisting people to travel abroad to commit suicide. Mrs Purdy asked for clarification this point and the DPP refused to issue further guidance.
House Lords heard Mrs Purdy’s judicial review request. The House of Lords held that the DP should issue guidelines.
Assisted suicide remains unlawful under the Suicide Act 1961. The new DPP guidelines still leave the situation unclear and mean those who assist someone to travel abroad to commit suicide may be liable for prosecution.
Consent is not a defence unless a public policy exception applies. These areas have been developed through case law and sometimes the extent of the consent may be limited.
Defendants participated in sado-masochistic homosexual activity and no one suffered permanent injury. Defendants argued the acts were consensual. The judge did not allow the argument so the defendant’s plead guilty to assault occasioning actual bodily harm and unlawful wounding.
On appeal the court had to decide whether consent should have been allowed to be raised. The court confirmed consent could be only be used in cases of battery because causing any greater injury was not in the public interest.
The court stated the defence of consent was only available in cases involving injuries more serious than common assault if they fell into one of the
recognised exceptions. A list was given including,
.. properly conducted games and sports, reasonable surgical interference and dangerous exhibitions....
Many sports involve some physical contact and risk injury inflicted by another so the key issue is the extent of consent.
Defendant inflicted a serious leg injury upon the victim. Defendant had attempted to make a sliding tackle during an amateur football match. Defendant accepted that the tackle had been hard, but maintained that it had been fair and that the injury caused had been purely accidental. Defendant was convicted of a S20 offence under the Offences Against The Person Act (OAPA) 1861.
Court of Appeal quashed the defendant’s conviction. The court held there is implied consent where the situation is within what can reasonably be expected and the game is conventionally played. Contact sports, including football, are
recognised exceptionson public policy grounds.
Court also ruled that criminal prosecutions should be reserved for grave situations. Noting that civil remedies are often available and most sports have disciplinary procedures, so prosecutions will usually be unnecessary. The following should be considered before a prosecution is brought: the type of sport, the level it was played at, the nature of the act, the degree of force, the extent of the injury and the state of mind of the person who caused the injury.
It is in the public interest to provide a consent defence and not to create criminal liability in normal sporting activities to allow for participation in contact sports.
There is implied consent in everyday minor touchings, for example, hand shaking or tapping someone on the shoulder to get their attention.
jostlingsexperienced in a crowd during everyday life cannot amount to battery (Wilson v Pringle (1987)).
A person can withdraw their consent and then such actions may lead to liability.
Surgical treatment can usually be consented to expressly, by a patient or parents on behalf of children, by signing a consent form. In emergencies there is implied consent. Medical consent may be refused or withdrawn at anytime.
Police Reform Act 2002
If a person is unable to give consent for a blood test, for a medical reason, for example he is unconscious then a police constable may request a sample is taken on his behalf. This gives statutory consent to a blood test.
Tattoos and piercings
Tattooing and body piercing can be consented and is regulated by statute such as Tattooing of Minors Act 1969.
Defendant branded, with a hot knife, his initials on his wife’s buttocks. The victim had requested the homemade tattoo. She had to seek medical attention for burns. Defendant was convicted of an offence under S47 under the OAPA 1861.
Court of Appeal found the branding was not an unlawful act despite the injury caused. It was found to be a situation of
personal adornmentand not in the public interest to criminalise such consensual acts.
Lord Mustill discussed, in a dissenting speech, the law on horseplay:
.. As a matter of policy the courts have decided that the criminal law does not concern itself with these activities, provided that they do not go too far. It also seems plain that as the general social appreciation of the proper role of the state in regulating the lives of individuals changes with the passage of time, so we shall expect to find that the assumptions of the criminal justice system about what types of conduct are properly excluded from its scope, and what is meant by 'going too far' will not remain constant....
Defendants, threw the victims, younger boys, into the air, giving them the ‘bumps’. The victims suffered a broken arm and an injured spleen.
It was held defendants were entitled to be acquitted if they were indulging in rough and undisciplined play or sport, not intending to cause harm and genuinely believing the injuries occurred in the course of horseplay with the victim’s consent.
Defendant, who knew he was HIV positive, had unprotected sex with the victims, who became infected. Victims claimed they did not know about his HIV and if they had done would not have engaged in unprotected sex. Defendant was convicted of S20 offences under OAPA 1861.
Court of Appeal found the victim needed to consent to the risk of catching the disease. Court also quashed conviction and ordered a retrial on the grounds of a misdirection.
Defendant, who knew he was HIV positive, had unprotected sex with three victims. Judge directed the jury to decide if the women had known before that the defendant was infected would this have affected their consent. If so, then there was no consent and defendant must be guilty.
Defendant had taken part in consensual ‘vigorous’ sexual activity with the victim. Defendant’s signet ring caused small cuts on the victim, which lead to blood poisoning and her death. Victim’s consent meant that there was no battery or assault and therefore no unlawful act. Defendant was found not guilty of manslaughter.
The consent must be genuine and the fact the victim appears to consent may not be sufficient.
Burrell v Harmer (1967)
Defendant tattooed the victims, 12 and 13 year old boys and caused actual bodily harm. Victims consented to being tattooed but the court would not allow the defence of consent. It was held that where a victim was unable to appreciate the nature of the act consent could not be truly given.
When a victim consents purely through fear it is a question of whether the threats are sufficient to induce the consent. This would be in line with the defence of duress.
Defendant raped the victim after she had watched him rape her friend. When defendant tried to have sex with the victim she submitted. Defendant argued this was consent.
Court of Appeal found that there was a distinction between real consent and mere submission and it was for the jury to decide if the consent was genuine.
Defendant asked women to take part in a breast cancer survey where he showed them how to carry out breast examinations. The victims, three women, not knowing the defendant had no medical qualifications consented but would not have done so had they known other than for medical purposes.
Defendant, a suspended dentist had carried out treatment on patients. Patients consented assuming the dentist but would not have done so if they knew the defendant was disqualified. Consent was accepted in this case and defendant not found guilty of assault.
The case law seems conflicting in this area and requires clarification.
Richardson and Irwin (1999)
Defendants and victim were students who often indulged in horseplay. Defendants had drunk around five pints when they dropped the victim from a balcony, believing he consented. Victim suffered serious injuries. Defendants convicted of S20 offences under the OAPA 1861.
Court of Appeal allowed the appeals and held their belief in the victim’s consent should have been considered.