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Testamentary Capacity

Testamentary Capacity

Written by:
Peter Fuscic
Niamh Forgie

When constructing a Will a will-maker has the freedom to decide how they wish to distribute their property upon their death, this is known as testamentary freedom. However, this freedom is not absolute. In certain circumstances, such as when a will-maker is said to have lacked capacity when they last made or altered their Will, a Will can be challenged and possibly be declared as invalid.

Testamentary capacity is the legal term used to describe a person's mental and legal capability to create or alter a Will.  Many factors may affect a person's testamentary capacity and result in impaired decision making, including being of advanced age, having an intellectual disability or having an illness such as dementia, a brain injury or a psychiatric disorder.

Whether a person had testamentary capacity is of considerable importance due to the effect that decisions made under their Will can have, especially in cases where the will-maker has many assets or capital.  It is also recognised that reduced mental capacity can mean a person is more susceptible to undue influence or duress in making a Will, on which grounds the Will can also be declared invalid.

How testamentary capacity is assessed

There is a presumption that a will-maker has testamentary capacity unless evidence is produced which raises doubt. The test for whether a will-maker has testamentary capacity is set out in case law and requires that the person must understand:

• The nature and effects of making a Will;

• The extent of the property being disposed of under the Will; and

• The moral claims of various family members or other potential beneficiaries, who they may be obligated to consider when making the Will.

When issues as to testamentary capacity arise

Issues of testamentary capacity most commonly arise where the will-maker is of advanced age or suffering from illness.  A dispute as to a will-maker's capacity can result in the executor and beneficiaries of the Will having to go through legal proceedings.

If the Court finds that a will-maker may not have had testamentary capacity at the time they signed their Will then it can be ruled as invalid and the Court may validate an older Will or make an order as to what happens with the Deceased's estate.

How we can help

Taking the appropriate steps and receiving adequate legal advice when you create or amend your Will can ensure that the wishes you outline are upheld following your death and that no claim as to your capacity can be established.

It is important that your lawyer assesses your testamentary capacity and that a medical certificate to back your capacity at the time you make or amend your Will is obtained if your lawyer advises.

On the other hand, you should consider seeking legal advice if you believe a loved one may not have had testamentary capacity when they signed their last Will or that they may have been influenced by someone else due to their mental capacity at the time.

If you have any enquiries relating to this topic or article, or require assistance with making or altering a Will please contact:

Peter Fuscic (Partner) on (09) 306 6746 (

© McVeagh Fleming 2023

This article is published for general information purposes only.  Legal content in this article is necessarily of a general nature and should not be relied upon as legal advice.  If you require specific legal advice in respect of any legal issue, you should always engage a lawyer to provide that advice.

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