MacDougall v Thomas: Undue Influence, Suspicious Wills and Key Lessons for Probate Disputes

A powerful reminder that suspicion alone is not enough to overturn a Will, but poor process, dependency and lack of independent advice can create years of expensive litigation.

For contentious probate lawyers, there is a familiar pattern. An elderly parent becomes increasingly dependent on one child, communication narrows, long‑held assumptions about inheritance shift, and a new Will emerges. After death, the same question inevitably arises: was this really what they wanted?

The High Court decision in MacDougall v Thomas [2026] EWHC 1142 (Ch) is one of the most significant inheritance disputes in recent years. It involved Alzheimer’s disease, allegations of undue influence, suspicious Will circumstances, disputed multimillion‑pound lifetime transfers and concerns about misuse of a Lasting Power of Attorney.

Jeanne MacDougall died in 2020 aged 91, leaving two children, Gary and Sandra. Earlier Wills broadly reflected equal treatment, consistent with longstanding family intentions.

However, after her husband’s death, Jeanne became increasingly close to Sandra and her husband, eventually living within their home and relying on them heavily. She was later diagnosed with Alzheimer’s disease.

Why did the dispute arise?

The answer is simple. The circumstances looked suspicious.

The Court identified several features which would make any contentious probate practitioner pause:

• advancing age

• Alzheimer's disease

• increasing dependency

• a dramatic change from earlier testamentary intentions

• significant involvement by beneficiaries

• very limited contemporaneous records

• no solicitor supervising execution

• no medical assessment of testamentary capacity

• no attendance notes explaining the decision-making process

Perhaps most strikingly, the adviser who prepared the Will kept no attendance notes at all. The Judge observed that this absence of records undoubtedly intensified the dispute.

As litigators, we see this repeatedly. The strongest probate cases are often not won by witnesses. They are won by documents. When those documents do not exist, suspicion flourishes.

What did the Court decide?

The outcome surprised many. Despite numerous concerns surrounding the Will-making process, the Court upheld the 2011 Will.

The Judge found:

• Jeanne had testamentary capacity

• she knew and approved the contents of the Will

• the evidence did not establish testamentary undue influence

In other words, the Court concluded that Jeanne understood she was effectively leaving her estate to Sandra and Philip and that this genuinely reflected her wishes. Suspicious circumstances existed, but they were ultimately explained.

However, and this is the crucial point, the Court simultaneously found that several later lifetime transactions were tainted by undue influence, lack of capacity or breaches of attorney duties.

That distinction is enormously important.

The critical difference between Will disputes and gift disputes

Many people assume undue influence means the same thing in every legal context. It does not. In a Will challenge, undue influence means something very close to coercion. The person making the Will must effectively be driven into making provisions they do not truly want.

The Court of Appeal recently reaffirmed that the threshold is exceptionally high. Influence, persuasion, dependency and opportunity are not enough by themselves. A testator may be persuaded. They may even be encouraged. They simply cannot be coerced.

As lawyers often explain: a testator may be led but not driven. That is why many Will challenges based on undue influence fail.

Lifetime gifts are different. Where there is a relationship of trust and confidence, and a transaction cannot easily be explained by ordinary motives, the law may presume undue influence. The burden can then shift. That makes lifetime gift challenges significantly easier than testamentary undue influence claims.

MacDougall is a perfect illustration of that distinction. The Will survived. Several lifetime transactions did not.

The warning signs every adviser should recognise

Cases like this rarely emerge without warning.

Looking back, there were numerous indicators that should have prompted caution.

1. Isolation of the testator

One family member increasingly became the centre of Jeanne's world.  The Judge heard evidence that communication with other family members became more difficult over time. Isolation does not prove wrongdoing. But it increases risk.

2. Control of communications

Many key communications came not from Jeanne herself but from those around her. Again, that may be entirely innocent. But when someone else consistently speaks for the testator, questions inevitably arise.

3. Involvement in Will preparation

Beneficiary involvement in the preparation of a Will is always dangerous. Even where nothing improper occurs, it creates fertile ground for future litigation.

4. Radical departure from previous Wills

One of the strongest predictors of a probate dispute is a significant change in testamentary intentions. Particularly where the change benefits the person most closely involved in the testator's life.

5. Dependency

Dependency is not evidence of coercion. But it is often the environment in which influence operates. The more dependent someone becomes, the more important procedural safeguards become.

The importance of independent advice

If there is one practical lesson from this case, it is this: Independent advice is worth its weight in gold. Not because it guarantees validity. Not because it prevents challenges. But because it creates evidence.

Evidence of:

• capacity

• understanding

• free decision-making

• informed choice

The Court repeatedly returned to the absence of contemporaneous records. Had detailed attendance notes existed, much of this litigation might never have happened.

The legal costs incurred in this dispute are almost certainly vastly greater than the cost of obtaining proper independent advice at the outset.

What this means in practice

For families, this case is not authority for the proposition that suspicious circumstances invalidate a Will.  Far from it. The Court was prepared to uphold a Will despite substantial concerns because the evidence ultimately persuaded the Judge that the Will reflected Jeanne's genuine intentions.

But it is also a warning. Where proper safeguards are absent, estates can become trapped in years of litigation. Families can be destroyed. Relationships can become irreparable. And large portions of an estate can disappear into legal costs.

Lessons for families and advisers

If you are helping an elderly relative with estate planning:

• Encourage genuinely independent advice.

• Avoid attending meetings unless necessary.

• Keep detailed records.

• Consider medical evidence where vulnerability exists.

• Record reasons for significant changes in testamentary intentions.

• Be particularly careful where one child receives substantially more than others.

Most importantly: Do not assume good intentions will be obvious after death.

Courts deal with evidence, not assumptions.

Lessons for contentious probate practitioners

This judgment contains several important practitioner points.

First, suspicious circumstances remain highly relevant even where a Will is ultimately upheld.

Second, vulnerability and dependency are not substitutes for proof of testamentary undue influence.

Third, claims concerning lifetime gifts may be considerably stronger than challenges to the Will itself.

Fourth, professional record-keeping matters.

A lack of attendance notes can transform an ordinary estate administration into a major High Court trial.

Finally, this case reminds us that probate disputes are rarely just about law.  They are about family dynamics. The legal arguments are often merely the final chapter in a story that has been developing for years.

Final thoughts

The most striking aspect of MacDougall v Thomas is not that the Will survived challenge.  It is that the Court simultaneously found evidence of undue influence and wrongdoing elsewhere.

That should make every adviser pause.  Because it demonstrates that vulnerability, dependency and influence can exist without necessarily invalidating a Will.

For practitioners, the case is a masterclass in the distinction between suspicion and proof.

For families, it is a reminder that transparency and independent advice remain the best protection against future conflict.

How Forbes Solicitors Can Help

Our specialist Contentious Probate team advises clients on a wide range of inheritance disputes, including claims under the Inheritance Act 1975, adult child claims, and cases involving disabled dependants or vulnerable beneficiaries.

If you believe you have been unfairly excluded from a Will, we can help you assess your options and the strength of any potential claim. For more information or to arrange a consultation call 0800 689 3607 to speak with a member of our team.