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Testamentary Mental Capacity Assessment

Testamentary capacity is the term used to describe someone’s testamentary capacity to make, or amend, a Will. As expert mental capacity assessors, our assessments are completed in line with the principles of the Mental Capacity Act (2005) and case law (Banks v Goodfellow (1870) LR 5 QB 549).


What the law says about testamentary mental capacity

The test for testamentary mental capacity, the mental capacity to write a will, is based in case law Banks Vs Goodfellow 1870. The Banks v Goodfellow test is a legal precedent applied in the United Kingdom, including Northern Ireland, when assessing whether a testaor has sufficient capacity to write a will. This judgement holds that mental capacity is decision-specific and was tested in the case of a person with schizophrenia who gave his sizable estate to a niece. The court declared that the validity of a will is unaffected by partial mental unsoundness, provided the testator understood the nature and extent of their property and the claims of those who warranted benefit when the document was written and executed. The courts stated, "It is essential...that a testator shall understand the nature of the said act and its effects; comprehend and appreciate the rights in which he should give effect; and his mind should be able to perform these tasks without being influenced by any mental disorders or delusions".

The test under Banks Vs Goodfellow states that a testator must be able to:


  • Understand the nature of making a will and its effects.

  • Undrestand the extent of the property involved.

  • Be able to comprehend and appreciate the claims involved.

  • Have no disorder of the mind that perverts your sense of right, or prevents you exercising your natural faculties when it comes to making or amending your will.

Your questions about testamenary capacity answered

  • Legal Terminology Explained
  • Testator: the person makign the will

  • Codicil: an addition or amendment to the original will.

  • Testamentary capacity: the capacity, or understanding, required to make a valid will as per Banks Vs Goodfellow (1870)

  • What to expect

Our testamentnary capacity assessments usually take around an hour, and our friendly, experienced social workers do their best to make sure it's a comfortable and relaxed experience. We're accredited expert mental capacity assessors, so you're in good hands.


  • What's Included in the assessment?

Everything necessary is included, an testamentnary capacity assessment either face to face or via video link as well as a corresponding report to be kept alongside your will and where necessary our Social Workers will complete additional assessments such as a Montreal cognitive assessment and a financial decision tracker to strengthen their reports at no additional cost.

  • Can we act as a witness?

Absolutely, if the testamentnary capacity assessment is taking place face to face and the Will is available on the day then, as long as testamentnary capacity is confirmed, then our Social Workers are happy to witness your Will being signed at no additional cost. 

  • Who can complete a mental capacity assessment?

In cases involving complex or major decisions, such as testamentnary capacity you may need to get a professional opinion. The assessor must be an impartial, qualified professional, such as a doctor, nurse, or social worker.

  • Can we complete video-link or face to face assessments?

We can visit you in your own home or any other suitable space you feel most comfortable and at a time of your choosing. In those instances where face-to-face testamentnary capacity assessments aren't viable, we offer a fully secure video-link testamentnary capacity assessment service. With the implementation of the Mental Capacity Amendment Bill (2019), we continue to provide video-link assessments, albeit as a last option and with a valid reason, duly recorded as evidence within our court-compliant reports




Social Work England is a specialist body taking a new approach to regulating social workers in their vital roles. All of our Social Workers are registered with Social Work England for your peace of mind. 


Our testamentnary capacity assessors are accredited Montreal Cognitive Assessment (MoCA) assessors with specific experience in completing capacity assessments and specialist reports.

All of our testamentnary capacity assessors have undergone extra training to become accredited financial vulnerability experts according to Lichtenberg standards, so they can provide even more detailed reports on mental capacity.


Gregg suffered a brain injury several years ago following a car accident. Since then, life had changed, and Gregg had divorced and remarried. 

Gregg now wished to create a new will to ensure his wife, Emelia, inherited his estate but also to ensure his children from his previous relationship were looked after should anything happen. 

While Gregg had a strong relationship with his children, his relationship with his first wife, Louise, had deteriorated, which had an impact on his relationship with his brother, Peter. Peter had suggested on several occasions that Gregg was "mentally unfit" leading Gregg to worry that any new will would be contested either by Louise or Peter. 

Gregg contacted a local will writer who advised him to have a testamentnary capacity assessment to go alongside his will to make sure everything was done correctly and to reduce the risk of his will being contested on the grounds of a lack of testamentnary capacity.

Our Social Workers attended Gregg at his home and completed a full testamentnary capacity assessment in line with case law (Banks Vs Goodfellow 1870) and a Montreal cognitive assessment to strengthen their testamentnary capacity report by evidencing how Gregg's brain was working on the day of the testamentnary capacity assessment.

Though Gregg initially saw the need for an testamentnary capacity assessment as an unnecessary hurdle, he understood that it reduced the risk of his will being contested later down the road. 

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Testamentary mental capacity assessment

Everything you need to know about testamentary capacity

Your mental capacity is a key attribute to the validity of any will. As a general rule, individuals making a will should have sufficient mental capacity in order to do so, as prescribed by case law. Read more in our article here.

Frequently Asked Questions

What is mental capacity assessment in relation to writing a will?

Our Social Workers offers a comprehensive Testamentary Capacity Assessment. The report verifies that you understand the details of your newly drafted Will and confirms its accuracy vis-a-vis your property, money, and possessions. We also check to make sure there hasn't been any undue influence when deciding who should receive your benefits. This report is vital in making sure your wishes in the Will are respected after you've passed away.

What is the difference between mental capacity and testamentary capacity?

Testamentary capacity is one aspect of mental capacity and it is the degree of legal competency required for a person to be able to make a valid will. Mental capacity is a broader concept and covers decision-making in all areas of life, not just in regards to creating a will.

What is the golden rule of testamentary capacity?

The golden rule clarifies that when a solicitor is uncertain about the testamentary capacity of an individual wanting to draft a will, evidence from a health or social care professional should be obtained. Moreover, the making of the will must be witnessed or approved by a health or social care practitioner after ensuring that the client in question possesses necessary competence.

Can someone with dementia have mental capacity?

To be legally binding, a will made by a person with dementia must be made when their decision-making abilities are unaffected by the condition. Our Social Workers can not only evidence the person's testamentary capacity on the day they make their will but also complete a Montreal cognitive assessment to evidence cognitive functioning on the day as well.


Who can assess mental capacity for a will?

In accordance with government  guidelines n appropriate assessors may include:

  Medical practitioners
  Social care professionals

It is imperative for these assessors to possess relevant professional qualifications, undergo training, and demonstrate practical experience that reflects their ability to assess capacity in accordance with the Mental Capacity Act 2005.

At Nellie Supports, all our Registered Social Workers are fully equipped as experienced assessors. In addition to meeting the standard requirements, they have received specialised training in Montreal Cognitive Assessments, ACE2, and handling cases involving financial vulnerability. This ensures that our Social Workers surpass the necessary qualifications for conducting assessments

What is a capacity assessment for making a will?

The ability to create a legally-binding will is predicated on the testator's ability to understand the consequences of their will. A capacity assessment for a will, conducted by a qualified professional, takes all pertinent factors into account; this includes prior medical and psychological history, mental state, cognitive examination, review of capability and consideration of any perceived manipulation or duress. In many cases, it is wise to use an expert psychiatrist to assess testamentary capacity and produce a report that can stand up in court if any challenge arises.


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