The Mental Capacity Act 2005 – implications for anaesthesia and critical care


  • *

    the terms ‘capacity’ and ‘competence’ are often used interchangeably; and will be for the purpose of this review.

Dr S. M. White


The Mental Capacity Act 2005 is due to come into force in April 2007. The Act provides a protective statutory framework for decision-making on behalf of incompetent adults, representing, in the main, a codification of the common law that had already developed in this area. For example, ‘advance decisions’ are now given formal statutory recognition. Importantly, the Act creates a new specialist ‘Court of Protection’ to manage the Act's enforcement, and an office of ‘Public Guardian’ to act as registering authority for new ‘Lasting Powers of Attorney’ and ‘court-appointed deputies’, both of which will be able to make proxy decisions about medical treatment for adult patients without capacity. There is also considerable regulation concerning the participation of adults without capacity in research. Given that their practice routinely involves the medical treatment of adults who lack legal capacity, anaesthetists and intensivists should familiarise themselves with the Act's key precepts.

The Mental Capacity Act 2005 [1] (‘the Act’) received Royal Assent on 7th April 2005, and is expected to come into force on the 1 April 2007. The Act clarifies the law concerning decision-making by others on behalf of mentally incapacitated* adults but, with a few notable exceptions, is simply a statutory formalisation of current common law in this area. However, the Act has several medicolegal ramifications that impact on the practice of anaesthesia and critical care in England and Wales, specifically regarding the process of consent, empowerment of proxy decision-makers, recognition of advance decisions (‘living wills’), withdrawal of life-sustaining treatment and the conduct of research on adults without capacity. Those ramifications are explained in this article.

The current law relating to capacity [2]

Legally, consent to medical treatment is valid if it is given voluntarily by an appropriately informed, competent patient [3]. Refusals of medical treatment are accorded similar legal status, provided the patient is appropriately informed, competent and acting voluntarily [4].

All adults are presumed to have the capacity to consent to medical treatment, unless that presumption is disproved [5]. Patients lack capacity if they are unable to make a decision whether to consent to, or refuse, treatment, such that if they cannot understand and remember the information provided, and/or cannot use that information when considering their decision. Patients are either competent to decide or incompetent. The more serious the decision to be made, the proportionately greater the level of capacity required [4]. It is usually the treating doctor who decides whether the patient is competent, although a secondary opinion from a colleague (usually a psychiatrist) or from the courts may be sought in equivocal cases. The doctor must be prepared to justify his decision to the court if asked.

Patients' decisions do not have to be sensible, rational or well-considered, although an irrational consent or refusal that is contrary to the evidence and not widely held by society might indicate that a patient is suffering from mental illness [6]. However, mental illness per se does not automatically render a patient incapable of making decisions about medical treatment.

No other person (including the courts or those with legal powers of attorney) may consent to medical treatment for an incapacitated (or other) adult. However, the courts have stated that doctors have a legal duty to provide all necessary treatment to incompetent adults according to the best interests of the patient. It should be noted that ‘best interests’ are more than just ‘medical best interests’, and represent a sum assessment of the patient's wider welfare [7].

Under section 8(1)–(3) of the Family Law Reform Act, 1969, 16- and 17-year-olds are presumed competent to consent to treatment unless it can be shown that they are incompetent [8], such that they fail the two-stage test of competence stated in ReMB (a patient is competent if s/he can take in and retain information, ‘use it and weigh it in the balance’) [5]. However, refusals of treatment by competent 16- and 17-year-olds, particularly if likely to result in serious harm or death, are likely to be overruled by the court.

Children under the age of 16 are rebuttably presumed to be incompetent to consent to treatment. However, a child who understands the nature and implications of the proposed treatment (termed Gillick competent [9]) can give valid consent. Proxy consent may be provided for incompetent children by parents, temporary carers, local authorities or the courts, provided the consent is given in the patient's best interests. In Scotland, under the Adults with Incapacity (Scotland) Act 2000, 16- and 17-year-olds have the same legal rights as adults to give consent to (or refuse) treatment. Children under 16 years can consent to treatment when, in the opinion of a qualified medical practitioner, they are capable of understanding its nature and possible consequences.

It should be noted that the Act refers only to patients over the age of 16. The capacity of an under-16 will continue to be determined by common law.

Background to the Act

The Act has its origins in the Law Commission Report No. 231 Mental Incapacity, published in 1995 [10] after a 5-year consultation exercise. The Report proposed a functional test for determining capacity, based on the common law position at the time (after Re C [11]), and recommended that there be a ‘general authority’ to treat incapacitated adults in their ‘best interests’, which, although not defined precisely, should include determination of:

  • • the ascertainable past and present wishes and feelings of the subject;
  • • their ability to participate (i.e. at least assent to what was proposed);
  • • proxy assessment of the subject's views (i.e. what friends, relatives and legal representatives think the patient might have wanted).

Two new and important recommendations were included in the Report, informed in turn by a report published in 1988 by the Centre for Medical Law and Ethics at King's College, London [12]. First, the Report proposed that advance statements about healthcare should receive formal legal recognition, such that an adult with capacity (if doing so voluntarily and having received appropriate information) could refuse any and all treatment in the event of their future incapacity, provided they specified exactly what treatments were to be refused and under which circumstances (ss.5.16–5.38). This had been the approach taken in Re T [4], and was reconfirmed after publication of the Report in the case of Re AK [13], in which a ‘locked-in’ 19-year-old with motor neurone disease did not receive artificial ventilation in accordance with his advance refusal.

Second, the Report proposed a registration scheme for ‘continuing powers of attorney’ such that, in the event of their anticipated incapacity, an individual (the donor) could appoint someone (the donee) to make future healthcare decisions on their behalf, in much the same way as proxy decisions may be made about the donor's property and affairs under the Enduring Powers of Attorney Act, 1985. Similarly, it was suggested that if an adult permanently lacked capacity, the courts could be empowered to appoint a suitable attorney on the patient's behalf (ss.7.7–7.58).

In 1997, the British Government produced a green paper ‘Who Decides? Making Decisions on Behalf of Mentally Incapacitated Adults’[14], which accepted many of the recommendations of the Law Commission Report, but sought further consultation on the proposals' suitability and practicality. This document stressed that the proposals (particularly those involving advance decision-making) were in no way designed to facilitate a move towards euthanasia or assisted suicide. In 1999, the Government produced a policy statement ‘Making Decisions’[15], which specified proposals to reform the law in England and Wales concerning decision-making for incapacitated adults. Comparable legislation, in the form of the Adults with Incapacity (Scotland) Act 2000, was introduced at this time to the Scottish parliament, after publication by the Scottish executive of their policy statement ‘Making the Right Moves’[16].

A draft Mental Incapacity Bill and explanatory notes were published in 2003 [17], going before a Joint Committee of both Houses for scrutiny [18] before introduction to the House of Commons in June 2004. In the interim between publication of ‘Making Decisions’ and the First Reading of the Bill, the Government had become signatories of the 35th Hague Convention on the International Protection of Adults [19], Article 3 of which envisages the circumstances under which an adult without capacity might require legal protection, including the provision of proxy consent for ‘personal’ intervention in order to protect that adult (3(d) and 3(g)). By agreeing the Convention, the Government indicated both its intent to introduce the Bill in England and Wales, and its support for such measures on an international stage.

Examination of the Joint Committee's report is highly instructive of the thought processes behind the introduction of this legislation. Notably, in considering whether legislation was even necessary, the Committee observed that criticisms had been directed more towards the proposals' contents, rather than the necessity of introducing a comprehensive statutory framework in this area. A considerable number of amendments were tabled, mainly to safeguard both patients from poor decision-making by their proxies, and doctors with conscientious objections to withdrawing treatment from patients. In addition, a lengthy section on research involving incapacitated adults was inserted, before the Bill finally received Royal Assent.

In the interim between Royal Assent and enforcement of the Act, its details have to be finalised by way of agreeing a Code of Practice. It is important to note that the published Draft Code of Practice [20] indicates that existing common law decisions will be vitally important in determining how the statute will be applied. In addition, it is acknowledged that the Act is not all-encompassing; for example, it does not seem to incorporate the notion that temporary factors such as pain, stress and anxiety may affect capacity, as was suggested in Re MB [5]. The Draft Code of Practice implies that common law will still be referred to by judges when making similar decisions in future, so that the ‘bare words’ of the Act will not be relied on alone when determining patients' legal capacity.

The Mental Capacity Act 2005 (Table 1)

Table 1.  Main points of the Mental Capacity Act 2005.
The Act comes into force in April 2007.
The Act applies to anyone aged 16 or over.
Main principles:
 Adults have capacity unless proved otherwise.
 Patients must be given a reasonable chance to demonstrate their capacity.
 The treatment of adults without capacity must be in their best interests.
An adult has capacity if they can understand, remember and use information that is appropriate to deciding whether to consent to or refuse treatment.
Lasting Powers of Attorney (LPA):
 May be granted to a donee by a competent patient who predicts future incompetence.
 Must be registered with the Public Guardian.
 May make proxy decisions about medical treatment in the patient's best interests.
 May refuse life-sustaining treatment for the patient, provided the patient has specifically empowered them to do so in writing.
Court-appointed deputies:
 Are appointed by the Court of Protection and registered with the Public Guardian, if no LPA has been created.
 May make proxy decisions about medical treatment in the patient's best interests.
 May not refuse life-sustaining treatment.
Advance decisions:
 Are legally binding if made by an appropriately informed, competent person, acting voluntarily, who describes what treatment is refused and under what circumstances.
 May prohibit the initiation or continuation of life-sustaining treatment.
Research involving adults without capacity:
 Is of secondary importance to the patient's welfare.
 Must be approved by a properly constituted Research Ethics Committee.
 Must be aimed at alleviating the condition from which the patient is suffering.
 Must only proceed if research on competent patients is impossible.
 Must potentially benefit the research subject.

The Act has three parts:

  • • Part 1 –‘Persons who lack capacity’– explains the principles underlying the Act, the definition of incapacity, the role of Lasting Powers of Attorney and court appointed deputies, the law concerning advance decisions, and the legal conditions required for involving incapacitated adults in research.
  • • Part 2 describes the institution and operating procedures of a Court of Protection, to whom applications and referrals are made concerning adults without capacity.
  • • Part 3 deals with miscellaneous and general matters, and, importantly, includes the declaration that ‘For the avoidance of doubt, it is hereby declared that nothing in this Act is to be taken to affect the law relating to murder or manslaughter or the operation of s.2 of the Suicide Act 1961 (c. 60) (assisting suicide)’ (s.62).

The five principles of the Act

Section 1 of the Act states the five principles on which the rest of the Act is based. Sections 2–7 clarify some of the definitions used in Section 1. Broadly, three concepts are outlined.

1) Adults have capacity unless proved otherwise

Section 1(2) states that: ‘a person must be assumed to have capacity unless it is established that he lacks capacity’, reflecting the common law position [5]. Section 2(1) states that: ‘A person lacks capacity … if at the material time he is unable to make a decision for himself … because of an impairment of, or a disturbance in the functioning of, the mind or brain’. Thus anyone over the age of 16 (s.2(5)) encountered in anaesthetic practice must be assumed to be competent to make decisions about their treatment unless they are manifestly unable to make a decision when required. The Act does not expressly prescribe when consent should be sought or a patient's capacity assessed; in theory, a patient may consent at any time before an intervention (i.e. even in the anaesthetic room directly before induction) provided they are able to make that decision, although in elective situations, it remains good practice to allow the patient time to reflect on the information provided [21].

The Act helpfully attempts to define what is meant by an inability to make decisions (s. 3(1)), by restating the two-stage test of capacity from Re MB [5], namely that the person should be able to understand and remember the information relevant to the decision, and use that information to arrive at a decision. Capacity is therefore a question of fact, albeit based on the balance of probabilities (s.2(4)): patients can either understand/remember/use the information given to them, in which case they have capacity and can provide or withhold valid consent, or they cannot, in which case they lack capacity and cannot consent or refuse an intervention.

However, by restating the common law, the Act fails to address two questions that commonly occur in clinical practice. First, do patients necessarily lack capacity if they cannot understand, remember or use all the information? Furthermore, should patients be expected to understand more if the risks of an intervention are greater? If so, this potentially renders patients ‘incapable’ and denies them autonomy in decision-making – which is surely against the intention of the Act. We know, for example, that patients can have difficulty understanding [22] and remembering [23] preoperative information. In addition, recall of pre-operative information may be affected by anaesthesia, surgery and disease [24], potentially leading to allegations of negligence against the anaesthetist if complications occur. Critics may see this as anaesthetists' failure to relay information in an appropriate manner, but without further guidance from the Act, it is unclear how far anaesthetists should go to ascertain true understanding and retention of information. Somewhat counter-intuitively, the Act notes that the person only has to remember the information for ‘a short period’ (s.3(3)); this may allow patients with borderline capacity to determine their treatment, but may also provide a defence for doctors when establishing exactly what a patient was told before a medical intervention.

A second question is: do patients lack capacity if they refuse to listen to the information offered, or defer their decision-making back to the anaesthetist? A professor of medicine, for example, would surely not lack capacity if, after listening to a proposed intervention, she declared ‘You do what you think is best’. Again, these circumstances would seem to disempower the patient, contrary to the intent of the Act.

Both of these questions re-inforce the importance of documenting the information given to patients about intended interventions or treatment. Additionally, it leads us to wonder whether anaesthetists should also record whether they made a formal assessment of a patient's capacity, and how they went about this process.

The Act does not attempt to describe either the extent or the standard of information that should be given to patients, merely that the information should be ‘relevant to the decision’. This reflects difficulties in the common law position, with the trend continuing away from the ‘reasonable doctor’ standard of Bolam [25] (doctors are obliged only to relay information to the same standard as their colleagues might) towards the ‘reasonable patient’ standard hinted at in Sidaway [26], Pearce [27] and Chester v Afshar [28] (doctors should tell the patient what a reasonable patient would want to know in those circumstances). However, the Act is explicit in pointing out that ‘information about the relatively foreseeable consequences of deciding one way or another or failing to make the decision’ must always be provided (s. 3(4)).

Although not explicitly stated, it appears that it is the person intending to perform the intervention who must decide whether the patient has capacity to consent or refuse (s. 5(1)(a)); i.e. during an operating list covered by a consultant and a trainee, either one should seek consent, depending on who is the operator. Theoretically, both may need to seek consent if both will be involved.

2) Patients must be given a reasonable chance to demonstrate their capacity

The second and third principles, respectively, state that: ‘A person is not to be treated as unable to make a decision unless all practicable steps to help him to do so have been taken without success’, and ‘A person is not to be treated as unable to make a decision merely because he makes an unwise decision’. Section 2(2) notes that (patients) may lack capacity temporarily (e.g. unconscious after a road accident) or permanently (either from birth, or acquired in adulthood). In addition, s.2(3) notes that ‘a lack of capacity cannot be established merely by reference to (a) a person's age or appearance, or (b) a condition of his, or an aspect of his behaviour, which might lead others to make unjustified assumptions about his capacity'. In terms of anaesthetic practice, therefore, anaesthetists must not assume that patients lack capacity just because they are receiving critical care, have received sedation or premedication, are subject to restraint under the Mental Health Act 1983, are acting irrationally, have consumed alcohol, are refusing what appears to be sensible treatment, are elderly or residents of a care home/nursing home, or are otherwise unable to communicate their decisions or questions verbally.

The Act obliges doctors to make reasonable efforts to provide information for patients with questionable capacity, so that they can decide their own treatment. This may require the anaesthetist, for example, to use simple language or pictures to explain an intervention, and to provide the means whereby patients can express their wishes non-verbally (letter charts, keyboards, blinked yes/no answers). Even then, if the communicated decision appears unwise or potentially life-threatening, a patient should not be declared incapable, although declaratory relief from the courts may be required in such circumstances.

3) The treatment of adults without capacity must be in their best interests

Principle 4 reiterates that decisions made on behalf of people lacking capacity must be in their best interests, i.e. the common law position stated in Re F [7]. However, the fifth principle requires regard to whether ‘…the purpose for which [the decision] is needed can be as effectively achieved in a way that is less restrictive of the person's rights and freedom of action', in order to protect patients under Articles 5 (Right to liberty and security), 8 (Right to respect for private and family life), 9 (Freedom of thought, conscience and religion) and 10 (Freedom of expression) of the Human Rights Act 1998 [29]. In other words, the medical treatment of adults without capacity must be both necessary and in their best interests.

Determining best interests requires consideration of more than merely what is medically best for patients, a reflection of the common law position (Re SL [30]):

  • • determination should not be made according to age, appearance, condition or behaviour (s.1). This seemingly innocuous statement has major resource implications, as it effectively prohibits rationing of expensive resources on the grounds of extreme age or chronic disease: in the absence of evidence to the contrary, the best interests of an emphysematous 95-year-old receiving ventilation for pneumonia must be regarded as qualitatively similar to that of an otherwise fit 30-year-old with the same condition.
  • • patients may, in time, recover their capacity and be able to determine their own treatment (s.3). This may allow doctors to defer treatment decisions until patients can decide for themselves;
  • • as far as reasonably practicable, patients should be encouraged to participate in treatment decisions, even if they are formally deemed incapable. Anaesthetists should consult patients' friends and relatives to determine their past and present wishes, feelings, beliefs and values (s.6) – although the test of best interests remains more than a substituted judgement (e.g. ‘It's what mother would have wanted'). Determination of patients' best interests remains a decision for the anaesthetist(s) in charge of their care; however, in future, there will be an onus on anaesthetists to consider seriously the views of any carers or donees of a Lasting Power of Attorney, or court appointed deputies (see below), or to comply with any valid advance decision (see below) (s.7).
  • • when determining best interests, a decision to withdraw or withhold life-sustaining treatment must not be taken with the intention of bringing about a patient's death (s.5). In practice, withdrawal of life-sustaining treatment is not viewed by the court as an offence, because death results from the condition the patient is suffering, rather than from the act of withdrawing treatment. Nevertheless, the presumption of the Act is that it is always in the best interests of patients for their lives to continue, although this presumption may receive less weight in any decision about best interests if prolonged intervention would be considered unnecessarily burdensome in someone, for example, with a terminal condition [31].

Medical treatment may be provided to a non-compliant patient who lacks capacity (e.g. an inebriated person with a head injury and fluctuating consciousness) provided that two circumstances exist. Firstly, the treatment must be in the patient's best interests (s.5(1)). Secondly, restraint that prevents harm to the patient is acceptable provided it is necessary and proportionate to the likelihood and seriousness of harm occurring (s.6(1–3)). In practice, anaesthetists would be wise to seek legal advice before restraining patients unless urgent intervention is reasonably required to prevent further injury (s.6(7)).

Lasting Powers of Attorney (LPAs) and court-appointed deputies (CADs)

Until the Act is finally enforced in 2007, it will remain the case that no-one may consent or refuse medical treatment on behalf of an adult without capacity, treatment being decided by the doctors on the basis of the patient's best interests. Once enforced, the new law provides for appointment of proxy decision-makers by patients (in the case of LPAs) or the Court of Protection (in the case of CADs), who can consent to or refuse treatment on patients' behalf in the event of their incapacity (as well managing their property and affairs).

Sections 9–23 of the Act deal with the appointment, function and regulation of LPAs and CADs. In general, the donees of an LPA will be created by a competent adult patient who is expecting to lose capacity in the future (e.g. patients with Huntintdon's chorea). The court may appoint CADs for adult patients who have never had capacity, or who have never appointed a donee of an LPA. The donees and deputies must themselves be over 18 years of age, and competent to make decisions on the patient's behalf (i.e. must understand, remember and use the information given to them) (s.9(2)(c)), and are only empowered if the patient lacks capacity at the material time that a decision needs to be made. Regaining of capacity by the patient (e.g. after critical care treatment of an acute illness) relieves the donee/deputy of their proxy powers. More than one donee/deputy may be appointed per patient and these may act independently or together (s.10(4)). Donees or deputies may not subtend their powers to other individuals, and may have their powers revoked either by the patient, having regained capacity to make such a decision, or by the court, if the donee/deputy is acting illegally or contrary to the patient's best interests (s.22(3)(b)(i) and s.16(8)(a)).

The authority invested in a donee/deputy extends to consenting to the initiation or continuation of a treatment, considered necessary by a doctor (s.11(7)(c)). They may also refuse treatment so long as it is not life-sustaining; donees of an LPA may refuse life-sustaining treatment, but only if the patient had specifically (and probably explicitly or in writing) authorised the donee to do so (Draft Code of Practice s.6.10 [20]). Court-appointed deputies, however, cannot make decisions about life-sustaining treatment (s. 20(5)).

Two new public bodies are created by the Act: the Public Guardian and the Court of Protection. The Public Guardian acts as the registering authority for LPAs and CADs, will supervise deputies, and will provide information to help the Court of Protection make decisions (s.57–60). Although unclear, it seems that a person will not be able to function as the donee of an LPA (and therefore give proxy consent to, or refusal of, treatment) unless the LPA is registered with the Public Guardian.

The Court of Protection will have jurisdiction relating to the whole Act and will be the final arbiter for capacity matters (s.45–57). It is the body invested with the authority to create deputies, and can be asked to make declarations or decisions about the conduct of donees of LPAs, or CADs, removing their powers if necessary. Moreover, the Court of Protection may be asked for a declaration if there is disagreement amongst or between professionals or donees/deputies about proposed treatment of adults lacking capacity. The Court can also be approached to clarify the details of an LPA, for example specific refusals of life-sustaining treatment.

The creation of LPAs and CADS is a new area of medical law that has not been challenged in the courts thus far. It is not envisaged that large numbers of LPAs and CADs will be appointed, at least initially. However, we consider that it would be sensible to seek advice from the hospital's legal department when a patient's personal welfare is partly determined by an LPA or CAD, until such time as clinicians become more familiar with the validity and authorities conferred by these appointments.

Finally, one further actor that anaesthetists may encounter once the Act is enforced is the Independent Mental Capacity Advocate (IMCA; s.35–41). An IMCA is someone appointed by an ‘appropriate authority’ (the Secretary of State for Health, with regard to medical matters) to support an adult without both capacity and any representative. The role of an IMCA is to indicate to decision-makers (e.g. CADs or doctors) the person's wishes, feelings, beliefs and values, and to provide information about all factors relevant to the decision. Although IMCAs can challenge decision-makers on behalf of persons lacking capacity, they cannot make decisions themselves about medical treatment.

Advance decisions to refuse treatment

Under common law [4, 11, 13], anticipatory refusals of treatment by adult patients (over the age of 18) are held to be legally valid if:

  • • a refusal of treatment is clearly established (for example, the patient refuses blood transfusion even if clinically indicated);
  • • at the time of the decision, the patient is competent and adequately informed, and makes the decision voluntarily;
  • • the decision is intended to apply in the circumstances that subsequently arise (for example, cardiopulmonary resuscitation should be attempted if the patient is involved in an road traffic accident, but not if the same patient requires ventilation on the intensive care unit as a consequence of future motor neurone disease).

These conditions form the future statutory basis of advance decision-making under the Act (s.24–26). Doctors should make reasonable efforts to ascertain the existence or provisions of an advance statement if they are informed of its existence, time permitting – though emergency treatment should not be delayed if there is any doubt. Advance decisions may be given orally or in writing using either medical or lay terms, but must specify the treatment that is to be refused. Decisions that concern life-sustaining treatment must be in writing and signed by the patient, or by another person in the patient's presence, and witnessed by a third person, who must countersign the statement (s.25(6)). Such statements must include an explicit refusal of life-sustaining treatment even if the patient's life is at risk (s.25(5)).

Doctors are bound to comply with an advance decision if the decision is both valid and intended to apply in the circumstances (s. 25(1)), and treatment in contravention of a valid, applicable advance decision may lead to a claim of battery or assault. Similarly, doctors may become liable in negligence if they withhold treatment according to an invalid advance decision, unless they can prove that they had reasonable grounds for believing that the decision was valid and applicable. Doctors are not required to comply with an advance decision if they have a conscientious objection to what is proposed. However, there remains an obligation to provide necessary emergency medical treatment, and to refer the patient to another doctor for continuation (or withdrawal) of treatment. It is important to note that the Act refers only to refusals of treatment; patients cannot demand specific treatments should they lose their capacity in future (Draft Code of Practice s.8.6 and 8.7 [20]). Advance decisions are invalid if they are withdrawn by a competent patient, superseded by power invested in the donee of an LPA, or manifestly contrary to a patient's expressed wishes (although the opinion of the Court of Protection should probably be sought in the last two instances).


The conduct of research involving humans has never been regulated by statute in the UK [32]. This will change with the enforcement of the Act (s.30–34), such that ‘intrusive research’ involving an adult without capacity will be unlawful unless certain criteria are met. ‘Intrusive research’ equates to research that could only normally be carried out if the research subject gives consent. Clinical trials of new drugs are specifically excluded from the Act (being regulated by the Medicines for Human Use (Clinical Trials) Regulations 2004 [33]).

All medical research involving incompetent adults must have approval from an ‘appropriate body’, to all intents and purposes a properly constituted and independent Research Ethics Committee, recognised by the Central Office for Research Ethics Committees (Draft Code of Practice s.12.7 and 12.8 [20]). The proposed research must be aimed at alleviating the condition from which the patient is suffering (s.31(2)), must only involve incompetent patients if the research answer cannot be obtained from research on competent, consenting patients (s.31(4)), and must potentially benefit the research subject (s.31(5)(a)), or aim to provide information that will benefit future patients with the same condition (s. 31(5)(b) – in which case, the research must carry a negligible risk). Such research might include, for example, a novel ventilation strategy for acute respiratory distress syndrome or the effects of hypothermia on severely head-injured patients.

The patients themselves, although lacking capacity to consent to participation in research, must not appear to object to the research (unless the research is aimed at alleviating discomfort or preventing harm), and may be withdrawn from the research if the researcher suspects that the conditions detailed in the previous paragraph no longer apply (unless s/he feels that the patient would be harmed as a risk of discontinuation). At all times the presumption should remain that the patient's welfare is of greater importance than the research in which they are participating.

Researchers must take steps to identify a third person (e.g. a carer) who is interested in the research subject's welfare and who may be consulted about the patient's proposed participation. If no such person can be identified, there is a duty imposed on the researchers to identify (with the help of an appropriate authority – usually a Research Ethics Committee) an impartial and independent adviser. Although the donees of LPAs (or CADs) may be the most appropriate third persons for researchers to approach, decision-making powers for the purposes of research may be extended beyond these people, for example, to the patient's relatives and friends. Such carers or advisers, acting in the patient's best interests, may withdraw the patient from participation in the research at any time if they feel that the patient would have so wanted. The researcher is obliged to comply with this, unless s/he feels that the patient would be harmed as a result of discontinuation. For example, a profoundly septic patient who was manifestly benefiting from a novel intravenous fluid regimen may continue to receive the therapy, even though the carer/advisor suggested that the patient – were they competent – might not want to receive the therapy as part of a research project.

In emergencies, researchers may enrol patients in research projects involving novel treatments if it is impractical to consult carers or advisers (as above), or if they have approval from an independent medical adviser or Research Ethics Committee. This may permit, for example, research into the use of new methods of chest compression during cardiopulmonary resuscitation. If the patient recovers capacity, they should be informed of their participation and asked if they wish to continue as a research subject (if applicable). If they fail to recover capacity, the researcher is obliged to seek carers/advisers who will act on the patient's behalf, as detailed above.

These regulations also apply if the patient loses capacity having previously given their consent to participation.


With one exception, there are no legal penalties described in the Act. Doctors who transgress the legal principles described in the Act will find themselves liable under existing criminal and common law. A doctor, for example, who continues therapy that is specifically prohibited by an advance decision may be liable in either the crime or the tort of battery, and be subject to custodial sentence or financial penalty.

The one exception concerns a new criminal offence of ill treatment or neglect of a person who lacks capacity (s.44). Doctors, donees or deputies may be found guilty of such an offence, and may be liable to a fine and/or imprisonment for a term of up to 5 years.

Despite its noble intentions, the Mental Capacity Act 2005 is a lengthy and cumbersome piece of legislation [34]. Critics might suggest that the Act is quintessentially ‘New Labour’, in that it changes the law very little, but redistributes decision-making power to government and the courts. Nevertheless, the Act will undoubtedly have a major impact on the clinical management of adults without legal capacity, a group of patients who are frequently encountered by anaesthetists and intensivists. Although the Act equates to current common law, several important new legal principles are created. We consider that most of the problems that arise out of the Act will be as a result of disagreement between doctors and newly empowered third parties (donees, deputies and IMCAs) concerning the continuation or discontinuation of specific medical therapies.

A good standard of contemporary medical practice is likely to render anaesthetists compliant with the Act when it is eventually enforced. However, we would strongly encourage departments of anaesthesia and intensive care to reconsider their clinical practice and programmes of education and training, in order to comply with Act before its imminent enforcement.