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Testamentary Capacity

A person who makes a will in Australia must have the requisite testamentary capacity. If there are doubts about the testamentary capacity of a testator, the will can be challenged. If the court finds grounds to invalidate a will, it will disregard the wishes set out in the will. The deceased estate will then be dealt with according to the provisions of a previous will or according to the rules of intestacy. Only certain people have the standing to challenge a will and can bring a challenge only if they can clearly substantiate their claim that the testator lacked testamentary capacity. This article defines testamentary capacity and set out the grounds for challenging a will based on testamentary incapacity in Australia.

What Is Testamentary Capacity?

Testamentary capacity is the mental acuity of a testator at the time they made their will. A will is only valid if the testator was of sound mind, understanding and memory when they wrote it. A testator is assumed to have testamentary capacity unless and until evidence is presented to a court to the contrary.

The legal test for testamentary capacity is based on the 1870 English case of Banks v Goodfellow (1870). Banks had a long history of mental illness and had been committed to an asylum for many years. When he died, he left his estate to his niece, who was a minor and who died several years after Banks without leaving a will herself. Her estate was inherited by her next of kin, which was a half-brother who was no relation to Banks. The son of Banks’ half-brother challenged the will based on a claim that Banks lacked the necessary testamentary capacity to make a will. The court, in that case, found that though the testator had a mental illness, the will was rational as it benefited his closest relative and was therefore valid, based on a four-part test. 

This early test of testamentary capacity has been reaffirmed numerous times since 1870, including in the 2015 NSW Supreme Court decision of Trustee & Guardian v Budniak

In order for a testator to satisfy a test of testamentary capacity in Australia, he or she must:

  • Understand the nature of a will and its effect on their deceased estate;
  • Know the general nature and breadth of their estate;
  • Understand who has a reasonable claim upon the estate and who should inherit; and
  • Not suffer from a medical condition or mental condition that prevents them from making rational decisions.

Conditions Impacting Testamentary Capacity

A person’s testamentary capacity may be challenged if they suffer from certain medical conditions that impact their mental faculties. These include psychosis, dementia, alcohol-related mental illness, personality disorders and psychiatric or neurological disorders. It is important to note that a person who suffers from any of these conditions does not automatically lack testamentary capacity. Testamentary capacity is measured based on the severity of the illness and the degree to which the person’s judgement, insight, and decision-making ability is impacted. The court will only deem a will to be invalid based on testamentary incapacity if it is presented with compelling medical testimony and other evidence to suggest that the necessary cognitive ability to make a will was absent.

Challenging A Will Based on Testamentary Incapacity

Circumstances that may give rise to a will being challenged include when the will was made just prior to death, or when the testator was:

  • Very ill when they signed the will;
  • Under institutional or medical care when they made the will;
  • Away from their family and friends when they made the will.

The list of people who can challenge a will based on a lack of testamentary capacity differs across different states and territories of Australia. Generally, those who have standing to challenge a will include the spouse and children of the deceased and registered caring partners and dependents.

Safeguarding An Estate Against Testamentary Capacity Challenges

The only way that a person can guard against challenges to their will based on testamentary incapacity is to establish proof of their mental capacity at the time the will was made. One approach is for a medical professional to examine the testator to assess their capacity at the time that they are making their will, and for this assessment to be stored with the original will.

Case Study

In the 2016 Queensland Supreme Court decision of Re Oliver (deceased), the testator had been diagnosed with schizophrenia and the will was found to be invalid based on testamentary incapacity.

In this case, the brother of the deceased challenged a will that had been prepared by the Public Trustee of Queensland. The deceased had suffered from schizophrenia his entire adult life and had been hospitalised from the age of nineteen until his death at sixty-one. For several decades, the Public Trustee had managed his financial affairs, and it applied for a Grant of Probate to administrate the deceased estate. The deceased’s brother sought to invalidate the will on the basis of the mental disorder and applied to be appointed administrator of the intestate estate. The court appointed the Public Trustee as administrator, due to concerns over the brother’s lack of impartiality.

The deceased died without a spouse or children, and his will left his estate to his sister (one of his four siblings). The Public Trustee argued that the testator’s will was rational as he had left his estate to a close relative and a presumption of validity therefore applied. The claimant presented evidence to overcome this presumption and the court was convinced upon hearing his submissions.

The court found that the will failed the Banks test on the following bases:

  • There were no explanatory notes justifying the testator’s decision to make his sister the sole beneficiary, or displaying awareness that he had other siblings who might have a legal entitlement to the estate; and
  • While a doctor had examined the testator at the time the will was written, the medical form was not particularly illuminating as to his capacity and showed no history of the doctor’s treatment of him.

If you have reason to believe that a family member lacked testamentary capacity when they made their will, please contact Go To Court Lawyers for advice. 


Nicola Bowes

Dr Nicola Bowes holds a Bachelor of Arts with first-class honours from the University of Tasmania, a Bachelor of Laws with first-class honours from the Queensland University of Technology, and a PhD from The University of Queensland. After a decade of working in higher education, Nicola joined Go To Court Lawyers in 2020.

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