Testamentary capacity is defined as the mental capacity of a testator while executing their will.
A case, (Banks v Goodfellow (1870) LR 5 QB 549) affirmed by multiple Australian authorities including the New South Wales Court of Appeal in (Mekhail v Hana  NSWCA 197) sets out the following as a test of testamentary capacity.
A test determining the capacity of a testator has been developed from (Banks V Goodfellow 1870) providing elements which may be utilised, stating a testator must.
- Have the capacity to understand the nature of the act of making a will and its effects
- Understand the extent of the property and subject of the will
- Have the capacity to comprehend the moral claims of potential beneficiaries.
- However, a testator must also not be suffering from a condition which will impact their cognitive decision making concerning the testamentary dispositions.
If a testator is found to lack testamentary capacity, the (Succession Act 2006 (NSW).(sections 18) provides that the Court may create, modify or revoke a will for persons who lack testamentary capacity.
Justice Kunc capacity, Ryan v Dalton 2017 and solicitor guidelines
(Ryan v Dalton  NSWSC 1007) regards an elderly man who created a second will leaving his estate to his defacto partner and children. He had originally not included his defacto partner on the grounds that they had an agreement to not include each other in their wills. The court then held that he did not contain sufficient mental capacity to create the updated will due to suffering from severe dementia, despite a solicitor taking his instruction, who stated he was in a “bright and talkative state”, contrary to carers of Ryan describing his behaviour as “irritable and disoriented”. The Judge, Justice Kunc took into account that while the solicitor aimed to take coherent and informative notes, she should have obtained the testators medical records. Kunc utilised this case as an opportunity to provide warning that adequate investigation of a testator’s mental capacity must be undergone.
Conveniently, Kunc J set out guidelines for solicitors to assess the capacity of testators, particularly the elderly. His Honour stated that investigation should be conducted if the testator:
- is over the age of 70:
- is managed by a carer:
- currently residing in a nursing home or similar facility:
- the solicitor has any other suitable reason to be concerned about capacity
Kunc J also states that “an interview should be undergone in private with only the testator, utilising open ended questioning may assist the solicitor in determining capacity without bias from external influences”.