ESTATE PLANNING // Understanding Mental Capacity and Succession Disputes: What You Need to Know
Planning for the future is essential, but inheritance disputes and questions about mental capacity can complicate even the best-laid plans. Whether you're concerned about a loved one's ability to make a valid will or worried about being left out of an estate, understanding the legal framework is crucial. In this guide, we’ll explore what mental capacity means in estate planning, why succession disputes happen, and how you can take proactive steps to protect your rights and prevent conflicts.
Authored in partnership with:
mahendree naidoo | Partner, lester aldridge | mahendree.naidoo@la-law.com
Estate planning is one of the most important aspects of securing your financial legacy, yet it is often overlooked. One of the biggest challenges in this area is determining whether a person had the mental capacity to make a legally valid Will. Additionally, disputes often arise when family members feel they have been unfairly left out or inadequately provided for in a Will.
1. What Defines Mental Capacity?
When discussing mental capacity in the context of estate planning, it’s essential to understand that capacity is not static—it can fluctuate over time. English law makes a distinction between two different types of capacity:
Capacity while alive – This is governed by the Mental Capacity Act 2005, which assesses whether a person can make fact-specific decisions (e.g., deciding where to live, handling finances, or selling property).
Testamentary capacity – This refers to the ability to make a legally valid will, which involves understanding the consequences of one's decisions.
For someone to be deemed to have testamentary capacity, they must:
Understand what a Will is and what it does – They must recognize that a will distributes their estate after their death.
Know the extent of their assets – This includes property, savings, investments, and other valuable possessions.
Be aware of who they should consider as beneficiaries – Including family members, dependents, or others with a reasonable expectation of inheritance.
Have the ability to weigh decisions rationally – They must understand how their choices will impact others, such as disinheriting a child.
Dementia and other cognitive conditions can impact a person’s ability to meet these criteria, but diagnosis alone does not automatically mean someone lacks capacity.
2. Why Do Succession Disputes Happen?
In recent years, disputes over Wills and inheritance have risen sharply. Several factors contribute to this trend, including:
Blended Families and Multiple Marriages
Modern families are often blended, meaning individuals may have children from different relationships. If a will does not adequately consider stepchildren or half-siblings, disputes may arise over inheritance.
For example, a person may intend for their estate to be shared equally among all children, but without a will, the law may only recognise biological or legally adopted children. Stepchildren may receive nothing unless explicitly included in a will.
Cultural and Religious Expectations
The UK does not enforce Sharia inheritance laws, but individuals from Muslim, Hindu, or other cultural backgrounds often want their estate to be distributed according to religious principles. If this is not clearly documented, disputes can occur between family members.
Additionally, individuals who own property overseas may be subject to different inheritance laws in countries like France or Spain, which enforce forced heirship (requiring a portion of the estate to go to specific relatives).
Rising Property Values
The increase in house prices and wealth has led to greater financial stakes in estate disputes. A home purchased for £30,000 decades ago may now be worth £600,000 or more, making inheritance disputes more financially significant than in the past.
Dementia and Mental Capacity Concerns
As life expectancy increases, so do cases of dementia and cognitive decline. If a will is made when someone’s mental capacity is in question, beneficiaries may challenge its validity, leading to lengthy court battles.
3. Can Cohabiting Partners Inherit?
One of the biggest misconceptions in inheritance law is that long-term partners automatically inherit their deceased partner’s assets. Under current UK intestacy laws, if someone dies without a Will, their estate is divided among legal spouses and blood relatives—not unmarried partners.
Even if a couple has lived together for decades, the surviving partner receives nothing unless they are specifically named in a will.
What Can Cohabiting Partners Do?
Make a will – The simplest way to ensure your partner inherits is by naming them in your will.
Consider joint ownership – If you own a house together, owning it as joint tenants means the surviving partner automatically inherits it.
Use the Inheritance (Provision for Family and Dependants) Act 1975 – If a partner was financially dependent on the deceased, they can make a claim for reasonable financial provision.
However, legal claims take time and money, so having a valid will is always the best option.
4. Medical Assessments and Capacity Disputes
If a Will is disputed on the grounds that the person who made it lacked capacity, medical evidence plays a key role.
How Is Capacity Assessed?
Medical records review – Doctors check for diagnoses like dementia and analyze how quickly the condition progressed.
Retrospective medical assessments – A specialist, such as an old-age psychiatrist, examines past records to determine whether the person likely had capacity when making the will.
Legal documents and witness statements – If a solicitor was present when the will was signed, their notes may provide evidence of capacity.
If a person lacked capacity when making their will, it can be ruled invalid, and the estate may be distributed under an older will or intestacy laws.
5. What Happens If You’re Left Out of a Will?
If someone feels they were unfairly left out of a Will, they may be able to challenge it through the Inheritance (Provision for Family and Dependants) Act 1975.
Who Can Claim?
Spouses/civil partners
Children (including stepchildren treated as part of the family)
Cohabiting partners (if living together for at least 2 years before death)
Anyone financially dependent on the deceased
How Does the Court Decide?
The court considers:
The applicant’s financial needs (including housing and medical expenses)
The estate’s total value
Whether the deceased had a valid reason for excluding the person
Any physical or mental disabilities affecting the applicant’s ability to support themselves
If successful, the court may award money, property, or ongoing financial support. However, legal challenges can be expensive and time-consuming, making estate planning essential.
6. How to Prevent Succession Disputes
The best way to avoid inheritance conflicts is through proper planning:
Make a Will – This ensures your wishes are legally recognised.
Review your will regularly – Update it after major life events (marriage, children, divorce).
Consider trusts – Trusts can protect assets and provide for stepchildren or vulnerable family members.
Discuss your wishes with your family – This can prevent misunderstandings and disputes later.
Seek legal advice – A solicitor can help structure your estate to minimize tax and legal issues.
