Today’s correspondent asks me to address the legal justification for treating the unconscious. My correspondent says:

I was wondering if … you could address a very common misapprehension I see repeated over and over again in first aid training sessions and by paramedics, and that is the concept of “Implied Consent” in unconscious patients.

I know you address the issue piecemeal in other blog posts, however I haven’t been able to find anything that addresses it outright.

I constantly see people talking about the reason we can treat unconscious patients is because of “Implied Consent,” which to me is ridiculous, someone who is unconscious cannot consent to anything, in any way, implied or otherwise!

It is indeed true that I have addressed the issue in other posts – see in particular The doctrine of necessity – Explained (January 31, 2017) and Refusing first aid revisited (May 12, 2019) and see generally the posts that appear here:  See also Michael Eburn’s Emergency Law (4th ed, Federation Press, 2013 pp 42-45).  It is also true that I have put out a post that ‘addressed it outright’, so I do that now.

Implied consent

It is not the law that a paramedic, first aider or anyone else can treat an unconscious person because of the doctrine of implied consent. Implied consent arises when the person’s consent can be implied by their actions, eg the patient who is in a queue to receive a vaccination, watches the people in front roll up their sleeve and get in injected, by implication also consents to receive the injection when it comes to their turn and they too roll up their sleeve and present their arm to the administering practitioner (O’Brien v. Cunard S.S. Co., 154 Mass. 272). The person who cooperates with treating paramedics/first aiders, presenting their arm to allow a blood pressure to be taken or a bandage applies, is consenting ‘by implication’.  That is implied consent. It is clearly NOT what is happening when a patient is unconscious.

Collins v Wilcock

In Collins v Wilcock [1984] 3 All ER 374 the issue was whether a police officer committed an assault when she grabbed a person by the arm. The officer had indicated that she wanted to ask the woman some questions and she’d made it clear that she did not want to answer them and was walking away. There were no lawful grounds to arrest (that is detain) the woman. Lord Goff said (at p. 378; emphasis added)

The fundamental principle, plain and incontestable, is that every person’s body is inviolate. It has long been established that any touching of another person, however slight, may amount to a battery… “the least touching of another is anger is a battery.” The breadth of the principle reflects the fundamental nature of the interest so protected. As Blackstone wrote in his Commentaries, 17th ed. (1830), vol. 3, p. 120:

“the law cannot draw the line between different degrees of violence, and therefore totally prohibits the first and lowest stage of it; every man’s person being sacred, and no other having a right to meddle with it, in any the slightest manner.”

The effect is that everybody is protected not only against physical injury but against any form of physical molestation.

But so widely drawn a principle must inevitably be subject to exceptions. For example, children may be subjected to reasonable punishment; people may be subjected to the lawful exercise of the power of arrest; and reasonable force may be used in self-defence or for the prevention of crime. But, apart from these special instances where the control or constraint is lawful, a broader exception has been created to allow for the exigencies of everyday life. Generally speaking, consent is a defence to battery; and most of the physical contacts of ordinary life are not actionable because they are impliedly consented to by all who move in society and so expose themselves to the risk of bodily contact. So nobody can complain of the jostling which is inevitable from his presence in, for example, a supermarket, an underground station or a busy street; nor can a person who attends a party complain if his hand is seized in friendship, or even if his back is (within reason) slapped (see Tuberville v Savage (1669) 1 Mod Rep 3, 86 ER 684). Although such cases are regarded as examples of implied consent, it is more common nowadays to treat them as falling within a general exception embracing all physical contact which is generally acceptable in the ordinary conduct of daily life….

In Re F

The most common justification for touching a person in first aid is that the person consents but some people cannot consent. It may be that they are unconscious, that they are affected by their illness or injury or for whatever reason they are not competent to give or refuse consent. How can their treatment be justified?  This was the issue that Lord Goff (again) had to consider in In Re F [1990] 2 AC 1. This was a case involving an application to permanently sterilize a developmentally disabled young woman. She could not consent to the surgery and given particularities of English law at the time, neither could her parents. The Court had to consider when could surgery or other treatment be given to a person who could not give consent.  Lord Goff said (pp. 22-27, emphasis added):

I start with the fundamental principle, now long established, that every person’s body is inviolate. As to this, I do not wish to depart from what I myself said in the judgment of the Divisional Court in Collins v. Wilcock [1984] 1 W.L.R. 1172, and in particular from the statement, at p. 1177, that the effect of this principle is that everybody is protected not only against physical injury but against any form of physical molestation.

Of course, as a general rule physical interference with another person’s body is lawful if he consents to it; though in certain limited circumstances the public interest may require that his consent is not capable of rendering the act lawful. There are also specific cases where physical interference without consent may not be unlawful – chastisement of children, lawful arrest, self-defence, the prevention of crime, and so on. As I pointed out in Collins v. Wilcock [1984] 1 W.L.R. 1172, 1177, a broader exception has been created to allow for the exigencies of everyday life – jostling in a street or some other crowded place, social contact at parties, and such like. This exception has been said to be founded on implied consent, since those who go about in public places, or go to parties, may be taken to have impliedly consented to bodily contact of this kind. Today this rationalisation can be regarded as artificial; and in particular, it is difficult to impute consent to those who, by reason of their youth or mental disorder, are unable to give their consent. For this reason, I consider it more appropriate to regard such cases as falling within a general exception embracing all physical contact which is generally acceptable in the ordinary conduct of everyday life.

It is against this background that I turn to consider the question whether, and if so when, medical treatment or care of a mentally disordered person who is, by reason of his incapacity, incapable of giving his consent, can be regarded as lawful. As is recognised in Cardozo J.’s statement of principle [in in Schloendorff v. Society of New York Hospital (1913)

105 N.E. 92, 93], and elsewhere (see e.g. Sidaway v. Board of Governors of the Bethlem Royal Hospital and the Maudsley Hospital [1985] AC 871, 882 per Lord Scarman), some relaxation of the law is required to accommodate persons of unsound mind. In Wilson v. Pringle, the Court of Appeal considered that treatment or care of such persons may be regarded as lawful, as falling within the exception relating to physical contact which is generally acceptable in the ordinary conduct of everyday life. Again, I am with respect unable to agree. That exception is concerned with the ordinary events of everyday life – jostling in public places and such like – and affects all persons, whether or not they are capable of giving their consent. Medical treatment – even treatment for minor ailments – does not fall within that category of events.The general rule is that consent is necessary to render such treatment lawful. If such treatment administered without consent is not to be unlawful, it has to be justified on some other principle.

Upon what principle can medical treatment be justified when given without consent? We are searching for a principle upon which, in limited circumstances, recognition may be given to a need, in the interests of the patient, that treatment should be given to him in circumstances where he is (temporarily or permanently) disabled from consenting to it. It is this criterion of a need which points to the principle of necessity as providing justification.

That there exists in the common law a principle of necessity which may justify action which would otherwise be unlawful is not in doubt. But historically the principle has been seen to be restricted to two groups of cases, which have been called cases of public necessity and cases of private necessity. The former occurred when a man interfered with another man’s property in the public interest – for example (in the days before we could dial 999 for the fire brigade) the destruction of another man’s house to prevent the spread of a catastrophic fire, as indeed occurred in the Great Fire of London in 1666. The latter cases occurred when a man interfered with another’s property to save his own person or property from imminent danger – for example, when he entered upon his neighbour’s land without his consent, in order to prevent the spread of fire onto his own land.

There is, however, a third group of cases, which is also properly described as founded upon the principle of necessity and which is more pertinent to the resolution of the problem in the present case. These cases are concerned with action taken as a matter of necessity to assist another person without his consent. To give a simple example, a man who seizes another and forcibly drags him from the path of an oncoming vehicle, thereby saving him from injury or even death, commits no wrong. But there are many emanations of this principle, to be found scattered through the books. These are concerned not only with the preservation of the life or health of the assisted person, but also with the preservation of his property (sometimes an animal, sometimes an ordinary chattel) and even to certain conduct on his behalf in the administration of his affairs…

We are concerned here with action taken to preserve the life, health or well-being of another who is unable to consent to it. Such action is sometimes said to be justified as arising from an emergency; in Prosser and Keeton on Torts, 5th edition, p. 117, the action is said to be privileged by the emergency. Doubtless, in the case of a person of sound mind, there will ordinarily have to be an emergency before such action taken without consent can be lawful; for otherwise there would be an opportunity to communicate with the assisted person and to seek his consent. But this is not always so; and indeed the historical origins of the principle of necessity do not point to emergency as such as providing the criterion of lawful intervention without consent… The most ancient group of cases in the common law, concerned with action taken by the master of a ship in distant parts in the interests of the shipowner, likewise found its origin in the difficulty of communication with the owner over a prolonged period of time – a difficulty overcome today by modern means of communication. In those cases, it was said that there had to be an emergency before the master could act as agent of necessity; though the emergency could well be of some duration. But when a person is rendered incapable of communication either permanently or over a considerable period of time (through illness or accident or mental disorder), it would be an unusual use of language to describe the case as one of “permanent emergency” – if indeed such a state of affairs can properly be said to exist. In truth, the relevance of an emergency is that it may give rise to a necessity to act in the interests of the assisted person, without first obtaining his consent. Emergency is however not the criterion or even a pre-requisite; it is simply a frequent origin of the necessity which impels intervention. The principle is one of necessity, not of emergency.

… the basic requirements, applicable in these cases of necessity, that, to fall within the principle, not only (1) must there be a necessity to act when it is not practicable to communicate with the assisted person, but also (2) the action taken must be such as a reasonable person would in all the circumstances take, acting in the best interests of the assisted person.

On this statement of principle, I wish to observe that officious intervention cannot be justified by the principle of necessity. So intervention cannot be justified when another more appropriate person is available and willing to act; nor can it be justified when it is contrary to the known wishes of the assisted person, to the extent that he is capable of rationally forming such a wish. … I hesitate at present to indulge in any greater refinement of the principle, being well aware of many problems which may arise in its application – problems which it is not necessary, for present purposes, to examine. But as a general rule, if the above criteria are fulfilled, interference with the assisted person’s person or property (as the case may be) will not be unlawful. Take the example of a railway accident, in which injured passengers are trapped in the wreckage. It is this principle which may render lawful the actions of other citizens – railway staff, passengers or outsiders – who rush to give aid and comfort to the victims: the surgeon who amputates the limb of an unconscious passenger to free him from the wreckage; the ambulance man who conveys him to hospital; the doctors and nurses who treat him and care for him while he is still unconscious. Take the example of an elderly person who suffers a stroke which renders him incapable of speech or movement. It is by virtue of this principle that the doctor who treats him, the nurse who cares for him, even the relative or friend or neighbour who comes in to look after him, will commit no wrong when he or she touches his body.

The two examples I have given illustrate, in the one case, an emergency, and in the other, a permanent or semi-permanent state of affairs. Another example of the latter kind is that of a mentally disordered person who is disabled from giving consent. I can see no good reason why the principle of necessity should not be applicable in his case as it is in the case of the victim of a stroke. Furthermore, in the case of a mentally disordered person, as in the case of a stroke victim, the permanent state of affairs calls for a wider range of care than may be requisite in an emergency which arises from accidental injury. When the state of affairs is permanent, or semi-permanent, action properly taken to preserve the life, health or well-being of the assisted person may well transcend such measures as surgical operation or substantial medical treatment and may extend to include such humdrum matters as routine medical or dental treatment, even simple care such as dressing and undressing and putting to bed…

I feel bound to express my opinion that, in principle, the lawfulness of the doctor’s action is, at least in its origin, to be found in the principle of necessity. This can perhaps be seen most clearly in cases where there is no continuing relationship between doctor and patient. The “doctor in the house” who volunteers to assist a lady in the audience who, overcome by the drama or by the heat in the theatre, has fainted away, is impelled to act by no greater duty than that imposed by his own Hippocratic oath. Furthermore, intervention can be justified in the case of a non-professional, as well as a professional, man or woman who has no pre-existing relationship with the assisted person – as in the case of a stranger who rushes to assist an injured man after an accident. In my opinion, it is the necessity itself which provides the justification for the intervention.


The Canadian case of Malette v Shulman [1990] 67 DLR (4th) 321 also considered implied consent. In that case Robins JA delivering the judgment of the court said (emphasis added):

The emergency situation is an exception to the general rule requiring a patient’s prior consent. When immediate medical treatment is necessary to save the life or preserve the health of a person who, by reason of unconsciousness or extreme illness, is incapable of either giving or withholding consent, the doctor may proceed without the patient’s consent. The delivery of medical services is rendered lawful in such circumstances either on the rationale that the doctor has implied consent from the patient to give emergency aid or, more accurately in my view, on the rationale that the doctor is privileged by reason of necessity in giving the aid and is not to be held liable for so doing. On either basis, in an emergency the law sets aside the requirement of consent on the assumption that the patient, as a reasonable person, would want emergency aid to be rendered if she were capable of giving instructions. As Prosser & Keeton, op.cit., at pp. 117-18 state:

The touching of another that would ordinarily be a battery in the absence of the consent of either the person touched or his legal agent can sometimes be justified in an emergency. Thus, it has often been asserted that a physician or other provider of health care has implied consent to deliver medical services, including surgical procedures, to a patient in an emergency. But such lawful action is more satisfactorily explained as a privilege. There are several requirements: (a) the patient must be unconscious or without capacity to make a decision, while no one legally authorized to act as agent for the patient is available; (b) time must be of the essence, in the sense that it must reasonably appear that delay until such time as an effective consent could be obtained would subject the patient to a risk of a serious bodily injury or death which prompt action would avoid; and (3) under the circumstances, a reasonable person would consent, and the probabilities are that the patient, would consent.


What do the Australian courts say? In Department of Health & Community Services v JWB & SMB (“Marion’s Case”) [1992] HCA 15the High Court said:

Consent is not necessary, however, where a surgical procedure or medical treatment must be performed in an emergency and the patient does not have the capacity to consent and no legally authorised representative is available to give consent on his or her behalf.

In the same year the High Court in In Rogers v Whitaker [1992] HCA 58, [14] said:

except in cases of emergency or necessity, all medical treatment is preceded by the patient’s choice to undergo it. In legal terms, the patient’s consent to the treatment may be valid once he or she is informed in broad terms of the nature of the procedure which is intended’.

The justification for treatment is the emergency or necessity, not implied consent. I have argued elsewhere that I do not see the High Court is suggesting there are two doctrines, one of emergency and one of necessity, rather they are using ‘emergency’ and ‘necessity’ as synonyms (see Emergency Law (4th ed, p. 44). The relevant doctrine is necessity.

See also ARC Guideline 10.5 – Legal and Ethical Issues related to Resuscitation  (November 2015) and the references there cited.

Compare necessity and implied consent

The problem with ‘implied consent’ is that it makes no sense when the patient could never consent eg they are very young, or permanently disabled, or where it is clear that they have refused consent to treatment. The principle of necessity as explained by Lord Goff deals with these issues, it is necessity not emergency that is relevant and it does not justify treatment that is contrary to the known wishes of the patient.

The doctrine of necessity justifies the person who finds a lost child and takes them by the hand to the local police station, the person who helps the patient with severe dementia take their daily shower, and the ‘good Samaritan’ and the paramedic who come to the road accident or sudden cardiac arrest and apply first aid.


Historically there has been some reference to implied consent but the courts and commentators accept that this is an historical error and the treatment of those who cannot consent is not justified by the doctrine of implied consent. It is justified by the doctrine of necessity.  The best explanation of that doctrine is given by Lord Goff –

… the basic requirements, applicable in these cases of necessity, that, to fall within the principle, not only (1) must there be a necessity to act when it is not practicable to communicate with the assisted person, but also (2) the action taken must be such as a reasonable person would in all the circumstances take, acting in the best interests of the assisted person.

… intervention cannot be justified when another more appropriate person is available and willing to act; nor can it be justified when it is contrary to the known wishes of the assisted person, to the extent that he is capable of rationally forming such a wish.

An instructor who tells their students that ‘implied consent’ is the lawful justification is wrong. But to be honest probably not much turns on it. If a person is unable to consent (whether because they are unconscious or they are not competent whether due to injury, illness or underlying disability) then treatment that is reasonable and in their best interests may be given. For most people most of the time the actual legal justification for that conclusion is not important.