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Contesting a Will Due to Dementia (UK Guide)

22 May 2025
An older couple consults with a financial advisor in a professional office setting, discussing financial plans and options.

Currently, there are estimated to be 982,000 people living with dementia in the UK, with this figure expected to rise to 1.4 million by 2040. Due to the impact that dementia has on decision-making, there are often particular concerns when it comes to creating a legally sound, accurate Will.

These concerns are often expressed as a dispute, where relevant parties (such as family) question the validity of the Will due to the “lack of capacity” of the person who wrote it - in other words, their ability to make proper decisions. This article will explore how to contest a Will due to dementia and the emotional implications you may experience during this process. If you require further legal support, please don’t hesitate to contact a member of our team today.

What Is Dementia?

Dementia is an umbrella term for a decline in cognitive function that interferes with daily life, such as your ability to speak, remember, or think. There are over 100 different types of dementia, such as Alzheimer’s disease, vascular dementia, Lewy body dementia, and fronto-temporal dementia. Although each type presents itself differently, some people may experience mixed symptoms from multiple forms.

What Is Testamentary Capacity?

Testamentary capacity refers to the legal and mental ability required to create a valid Will. At the time of writing the Will, a person must fully understand the nature and consequences of their actions regarding their estate. Importantly, even if an individual is diagnosed with dementia, they may still possess testamentary capacity - provided that their condition does not impair their ability to make informed decisions when drafting their Will.

The Four-Part Test

Banks v Goodfellow (1870) is a landmark case that established the legal test for testamentary capacity. In the case, John Banks, despite suffering from delusions, made a Will that was later challenged on the grounds of incapacity. The court claimed that as long as the delusions did not influence the specific dispositions made in his Will, his testamentary decisions were still valid.

The case set out a four-part test for assessing testamentary capacity:

  • The testator must understand the nature and effect of making a Will.
  • They must have a general knowledge of the value of their property.
  • They need to be aware of the claims of those who might normally expect to benefit.
  • They must not be affected by any mental disorder that would affect their decisions about the distribution of their assets.

The Golden Rule

The “Golden Rule” is a legal guideline that advises solicitors to seek an expert opinion when determining the capacity of a testator (the Will-writer). The professional’s findings will be documented to prove capacity at the time that the Will was made.

Solicitors use the Golden Rule when there are doubts about the testator’s capacity, such as if they suffer from dementia or other related issues which affect their cognitive behaviour.

What Are the Signs That Someone Lacks Capacity?

A woman sitting on a couch, resting her hands on her head, appears deep in thought or stressed.

Someone who lacks capacity is believed to be unable to make decisions if they cannot:

  • Understand information about a decision.
  • Remember the information about a decision.
  • Use that information to make a decision.
  • Communicate a decision by speaking (or by other means).

What Other Conditions Can Affect Capacity?

Several other conditions may cause an individual to lack capacity, as outlined in the Mental Capacity Act 2005 (MCA). These include:

  • Severe learning disabilities
  • Mental health conditions (e.g. schizophrenia)
  • Strokes
  • Brain injuries

What Problems Can Arise When Someone Lacks Capacity?

One of the biggest concerns when someone has been diagnosed with a condition like dementia is that their capacity can “change” each day. Those who are close to someone with dementia will know well that the symptoms can fluctuate; the individual may be more aware of decisions on one day and less so on the next. This becomes more problematic in the context of Will-writing or amending a Will, as it can be hard to prove the capacity of the testator at that exact time.

What Evidence Is Needed to Prove Someone Lacks Capacity?

If you feel a family member lacked capacity at the time of writing their Will, there are several forms of evidence that you should present to the Court of Protection, such as:

Legal Records

The file of the solicitor who took instructions and prepared the Will should include evidence of capacity. The file should include a comprehensive attendance note prepared by the solicitor taking the Will instructions, going through the steps in the Banks v Goodfellow test as well as setting out what the testator wanted and their reasons for making the choices they have can be strong evidence of a testator’s capacity. A similar attendance note should have been prepared if the solicitor was present when the Will was signed.

Medical Records and Cognitive Assessments

To prove a lack of capacity, documentation from a capacity specialist who has knowledge and experience in performing such assessments can be used. If no such assessment was undertaken at the time the Will was signed, then medical records can be used as evidence of a person’s mental state. These records should clearly indicate cognitive decline, such as through test results highlighting impaired memory, orientation, and decision-making.

Witness Testimonies and Documented Irregularities

The court may consider witness testimonies from family, carers, or professionals who were present during the creation of the Will. Such testimonies can provide context about the cognitive issues observed, inconsistencies in the testator’s behaviour, or even signs of undue influence (where someone uses their power to unfairly influence another’s decisions). Documentation that captures irregularities in the Will-making process can further support the argument that the testator lacked capacity.

Burden of Proof and Presumption of Capacity

The presumption is that a correctly executed Will is valid unless proven otherwise. Therefore, the “burden of proof” lies with the party contesting the Will to prove that the Will is not valid due to lack of knowledge on the part of the testator. They must provide substantial and compelling evidence - both medical and testimonial - to overcome the presumption of capacity and demonstrate that the testator was unable to understand the nature and consequences of the Will at the time of its execution.

How Can I Contest a Will on the Grounds of Dementia?

Three people seated at a table, collaborating with a laptop and scattered papers in front of them.

If you feel there are significant grounds to contest a Will on the grounds of dementia, here’s a brief overview of the typical process:

  1. Seek Legal Advice: Start by consulting with a solicitor who’s experienced in Will disputes - they’ll talk you through some of the potential outcomes of your case.
  2. Gathering Evidence: Obtain necessary evidence, such as medical records, cognitive assessments, witness testimonies, previous Wills, or the solicitor’s file.
  3. Assess the Evidence: Your solicitor will assess the evidence you’ve provided to determine whether you have a strong case to contest the Will.
  4. Alternative Dispute Resolution (ADR): If possible, your solicitor will attempt to mediate with relevant parties, since this is less costly and stressful than the court.
  5. Court Proceedings: If the evidence supports a challenge and no other alternative is feasible, the solicitor will initiate court proceedings to contest the Will.
  6. Case Outcome: The court will decide on the validity of the Will, taking into account the evidence that they’ve been provided, and come to a conclusion. If the outcome is unfavourable, you can consider an appeal.

What Happens When You Contest a Will?

When you contest a Will, some of the potential outcomes include:

  • Invalidation or Modification: The court may invalidate the entire Will or specific provisions, resulting in a redistribution of assets.
  • Intestacy Outcome: If the Will is largely overturned, the estate may be distributed under intestacy rules, which might differ significantly from the original intent.
  • Potential for Settlement: Parties may reach a negotiated settlement outside of court, avoiding a full trial but still altering the intended distribution.

What Are the Emotional Implications of Contesting a Will?

Legal cases can be emotionally taxing, often triggering or exacerbating mental health issues such as anxiety due to the uncertainty of the case outcome. Significant tension can cloud family relationships, especially if the process has been perceived as unfair or disrespectful by some parties. Above all, these disputes often occur at a time when you’re already enduring a great deal of grief after losing a loved one, making it harder to process the grief and move forward.

However, legal experts (such as our disputes team at Culver Law) are here to make the process as smooth as possible. Solicitors are not only tasked with finding the best outcome but they are also dedicated to providing the right emotional support during the dispute. Factors such as regular, open communication can help reduce feelings of anxiety and isolation, giving you confidence in your case.

What Happens if the Executor of a Will Develops Dementia?

If an executor of a Will has dementia and can no longer effectively carry out their duties, they may need to be removed (or step down themselves). In these circumstances, an alternative executor named in the Will, or a court-appointed administrator, would take over to ensure that the estate is properly distributed, as outlined in the Will.

Our Legal Experts Can Support You With Will Disputes

Our testamentary capacity dispute solicitors can support you by examining evidence, organising mediation methods, and providing litigation support if necessary, giving you peace of mind at a stressful time.

In addition, Amy Wallhead (Firm Partner, based at our Cambridge Office) is a Dementia Friends Ambassador and is passionate about supporting and guiding those either living with Dementia, or their family and loved ones during difficult legal and emotional challenges.

If you’re looking for a compassionate, knowledgeable, and client-centric service, please contact us today. Don’t navigate this complex matter alone - we’re here to help.

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Any information on this website, whilst intended to be accurate, does not constitute legal advice.
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