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Guidelines on Capacity and Testamentary Capacity
(published March 2006)

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General Legal Rules

  1. Mental capacity is a legal concept and any decision as to whether a person does or does not have mental capacity is ultimately a decision for a court of law [1]. A doctor assessing mental capacity does so as expert witness for the court and owes a duty to the court as well as to the person assessed.
  2. Assessment of capacity applies to individual decisions: an individual may be capacious in some decision making but not in others.
  3. A medical report on testamentary capacity, that is the mental capacity to make a will, must have regard for the legal rules as set out in the relevant case law. The current legal requirements in England and Wales, Scotland and Northern Ireland are set out below.
  4. There are legal presumptions of competence and continuance. Thus (i) a person is presumed to be competent until the contrary is proved and (ii) once it has been proved that someone is incompetent then this is presumed to continue until the contrary is proved.
  5. A decision as to whether a person lacks or has testamentary capacity is made on the balance of probabilities. The assessing doctor should therefore address the question: "Is it more probable than not that this person lacks or has testamentary capacity?" The standard of proof is not "beyond reasonable doubt" as used in criminal cases.
  6. a. Any assessment of mental capacity must be made with reference to a particular task. Thus, testamentary capacity has to be determined with regard to a particular will. The more complex the disposition, the greater the mental capacity necessary. The doctor has to have some idea of the extent and complexity of the estate and the number and nature of likely claims. b. These same considerations also apply when assessing an individual’s capacity to determine their own care needs and their ability to judge risk, e.g. when considering care home placement vs care at home.
  7. Doctors who have to treat a patient who is unable to give consent to treatment may need to seek the guidance of the court before making a decision to treat or not to treat. Such an application is not needed in every case. Where the issues of capacity and best interests are “clear and beyond doubt”, an application to the court is not necessary. But “where there is any doubt as to either capacity or best interests, an application to the court should be made” [2]. Five specific instances may occur when a judge would expect doctors to seek the Court’s guidance on how a patient should be treated. These are:
    • where there is any doubt or disagreement as to the capacity (competence) of the patient;
    • where there is a lack of unanimity amongst the medical professionals as to either (i) the patient’s condition or prognosis or (ii) the patient’s best interests or (iii) the likely outcome of the proposed treatment being either withheld or withdrawn or (iv) otherwise as to whether or not the treatment should be given or withdrawn;
    • where there is evidence that the patient when competent would have wanted the treatment to either be given or not given, and this is contrary to the views of the clinicians;
    • where there is evidence that the patient (even if a child or incompetent) resists or disputes the proposed treatment;
    • where persons having a reasonable claim to have their views or evidence taken into account (such as parents or close relatives, partners, close friends, long-term carers) assert that proposed course of treatment or failure to treat is contrary to the patient’s wishes or not in the patient’s best interests.

The Medical Assessment

  1. Mental incapacity can arise either by reason of a mental disability (including frontal dysexecutive syndrome, mood and thought disorder) or by reason of the fact that the person cannot communicate for any reason [3]. The mere presence of mental illness does not define mental incapacity. Patients detained under the Mental Health Act 1983 or patients who are under the care of the Court of Protection may have testamentary capacity.
  2. The assessing doctor should make a clinical assessment of the person and review the relevant medical notes. It may be necessary to seek the advice of others as part of the assessment. Clinical psychologists, nurses, social workers and relatives may provide valuable information. It is prudent to discuss the use of such information with the instructing solicitor before seeking it. Care must be taken when relying on information from relatives who may have a financial interest in the outcome of the assessment.
  3. There is no standard test of capacity, e.g. Mini-Mental State Examination (MMSE).
  4. The assessing doctor owes a duty of confidence to the person being assessed. Information relating to the content of the will should not be passed on to other parties except with consent. In exceptional cases disclosure can proceed without the person’s consent [4]. Such disclosures should be initially discussed with the instructing solicitor.
  5. The assessing doctor should seek to enhance the mental capacity of the person. If full recovery from a recent insult has not occurred or there are treatable disabilities which interfere with capacity then these facts should be conveyed to the solicitor and the person fully advised. A person with borderline mental capacity will perform badly in a hostile environment. The assessing doctor should take steps to ensure that the person is given the best possible chance to demonstrate his or her mental capacity. The doctor should be aware that capacity fluctuates and that a will made during a lucid interval may be upheld.
  6. 6. On rare occasions the assessment may cause problems with the doctors ongoing medical relationship with the patient. If this is likely then it is prudent to refer the solicitor to another practitioner.

Retrospective Assessment

  1. Doctors may be asked for a retrospective assessment of capacity. In such cases the legal principles remain the same although the evidential problems become greater.

The Law in England and Wales

  1. The criteria for testamentary capacity were set out in the case of Banks v Goodfellow [5], where it was said that the testator shall:
    • understand the nature of the act and its effects
    • understand the extent of the property of which he is disposing and
    • appreciate the claims to which he ought to give effect.
  2. It is to be noted that the criteria refer to the extent and not the value of the property.
  3. It is not necessary that the testator behave in a wise and prudent fashion [6].
  4. Although it may be appropriate to explain in broad terms the nature of will making and remind the person of the extent of his assets, the person must be able to appreciate and comprehend the claims to which he ought to give effect without any assistance [7]. The mental capacity required to revoke a will is the same as that required to make one [8].
  5. If a person lacks the capacity to make a will an application can be made to the Court of Protection for a statutory will. Whether this is done is a matter for the person's solicitor bearing in mind the cost of such an application.
  6. The Mental Capacity Act 2005 [9], which comes in to force in 2007, sets out the clear legal requirements for assessing competence in adults aged over 18 and may also be used in those aged 16-17 whose incompetence is likely to persist in to adulthood. A person lacks capacity if they fail one of the following criteria:

(a) understanding the information relevant to the decision
(b) retaining the information (even if only for a short period)
(c) using or weighing that information
(d) communicating the decision (by any means)

An unwise or irrational decision is not necessarily an incompetent decision.

The Law in Scotland  

  1. To have testamentary capacity the person must comprehend what a will is and what would be the consequences of making one [10]. Scottish courts are likely to follow the tests defined above for the making and revocation of wills under English law.
  2. A will under Scottish law may be set aside for facility and circumvention. Facility is "a weakness of the mind .... such that the person can be easily imposed upon and induced to do deeds to his own prejudice", but not amounting to incapacity [11]. Circumvention is an "intimidation operating on the mind as to bring the individual within entire control" [12]. To enable a will to be set aside both facility and circumvention must be present. The greater the degree of facility the lesser the amount of circumvention necessary in order to set aside the will [13]. The decision as to whether a will should be set aside on this ground is obviously one for the court. The medical evidence in such a case goes to defining the degree of facility.
  3. There are no provisions for the use of statutory wills under Scottish Law.
  4. The Adults with Incapacity ( Scotland ) Act [14] states: ‘For the purposes of this Act, and unless the context otherwise requires- "adult" means a person who has attained the age of 16 years; " incapable" means incapable of-
    • (a) acting; or
    • (b) making decisions; or
    • (c) communicating decisions; or
    • (d) understanding decisions; or
    • (e) retaining the memory of decisions,

    as mentioned in any provision of this Act, by reason of mental disorder or of inability to communicate because of physical disability; but a person shall not fall within this definition by reason only of a lack or deficiency in a faculty of communication if that lack or deficiency can be made good by human or mechanical aid (whether of an interpretative nature or otherwise); and "incapacity" shall be construed accordingly.’

The Law in Northern Ireland

The law in Northern Ireland is similar to that in England and Wales.


  1. Richmond v Richmond (1914) 111 LT 273
  2. Burke vs General Medical Council 2004.
  3. The Law Commission 1995. Mental Incapacity Report 231
  4. GMC 1995. Duties of a doctor.
  5. Banks v Goodfellow (1870) LR 5 QB 549
  6. Bird v Luckie (1850) 8 Hare 301
  7. Cartwright v Cartwright (1793) 1 Phill Ecc 90
  8. re Sabatini (1970) 114 SJ 35
  9. Mental Capacity Act 2005:
  10. Sivewright v Sivewright (1920) SC (HL) 63
  11. Gibson v Alexander (1925) SLT 517
  12. Love v Marshall (1870) 9 M 291 at 297 per Lord Kinloch
  13. Anderson v Beacon (1992) SLT 111.
  14. Adults with Incapacity ( Scotland ) Act:

Further reading

Ashton G R, The Elderly Client Handbook. The Law Society's guide to acting for older people. The Law Society, 1994

British Medical Association / Law Society (2004) Assessment of Mental Capacity. Guidance for Doctors and Lawyers. London : BMJ Books.

Bellhouse J., Holland A., Clare I et al, (2001) Decision-making capacity in adults: its assessment in clinical practice. Advances in Psychiatric Treatment, 7, 294-301.

Berghmans R.L.P. (2001) Capacity and consent. Current Opinion in Psychiatry,14, 491-499.

BMA’s consent tool kit:$file/toolkit.pdf (Must be BMA member to access)

GMC website: (Click on Ethical guidance → Guidance on good practice → Consent)


Public Guardianship Office, Archway Tower , 2 Junction Road , London , N19 5SZ .



British Medical Association, Ethics Department, BMA House, Tavistock Square , London , WC1H 9JP . 0171 387 4499

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