When Does The Burden of Proof Shift in Will Disputes?

About Our Legal Expert: This content is produced with oversight by Michael Jefferies, Managing Director who has more than 30 years’ legal experience.

Written by Tanya Waterworth, Digital Content Writer

Who Must Prove What in a Will Challenge

• A properly executed Will is presumed valid.
• The challenger must usually raise evidence casting doubt on the Will.
• The burden of proof may shift in capacity and knowledge and approval disputes.
• The burden usually remains with the challenger in undue influence claims.
• Medical records and solicitor files are often crucial evidence.
• A caveat can prevent Probate being granted while concerns are investigated.

Family conflict over a Will when a loved one dies is not unusual, but before contesting a will it’s useful to know about the burden of proof in will disputes and when it may shift from the challenger to the defender of a Will. Families tend to expect the administration of an estate to be straightforward in England and Wales.

But concerns can arise when a vulnerable person suddenly changes their Will shortly before death, when one family member appears to have influenced the deceased or even when something about the document or the circumstances surrounding its signing seems wrong.

While you cannot contest a will simply because you may feel it’s unfair in some way, if there are red flags about a Will, you may want to start a contentious probate claim. Burden of proof is an important legal concept, and we look at who must prove their case, as well as evidence needed to build a strong case and when the burden of proof may shift.

The Starting Point: The Will Is Presumed Valid

Many people assume that the executor must prove that a Will is valid. In reality, the legal position is often just the opposite. If a Will appears to have been correctly signed and witnessed under the Wills Act 1837, the court begins with the presumption that the document is valid and reflects the deceased’s wishes.

This means a person challenging the Will must do more than simply express concerns or dissatisfaction with its contents. They must be able to provide evidence capable of creating genuine doubt about the validity of the document. Only once those concerns are supported by evidence, will the court examine whether the burden should shift to the party seeking to uphold the Will

What Grounds Can Be Used to Challenge a Will

Several legal grounds can be used to challenge the validity of a Will, for example:

1. Lack of Testamentary Capacity

Disputes often arise when the deceased suffered from conditions such as dementia, Alzheimer’s disease, cognitive impairment, mental illness or the effects of medication.

It’s worth knowing that to make a valid Will, the testator must understand:

• That they are making a Will.
• The nature and extent of their assets.
• The people who might reasonably expect to benefit from their estate.
• The effect of the decisions contained within the Will.

2. Undue Influence

Undue influence occurs when somebody pressures, coerces, or manipulates a person into making a Will that does not reflect their true wishes. These cases are often difficult because direct evidence is rarely available. The alleged influence usually happens behind closed doors and can involve emotional manipulation rather than overt threats.

3. Fraud or Forgery

A Will can also be challenged if there is evidence that fraud or forgery may have occurred, for example:

• The signature was forged.
• Pages were altered after execution.
• The deceased was deceived into signing the document.
• False information was provided to procure the Will.

4. Lack of Knowledge and Approval

Even where the deceased had mental capacity, a Will may still be invalid if they did not understand or approve its contents. These claims frequently arise when suspicious circumstances surround the preparation of the Will.

When Does the Burden of Proof Shift?

One of the most misunderstood aspects of contentious probate claims is that the burden of proof does not necessarily remain with one party throughout the dispute.

However, if a challenger produces evidence creating real doubt about capacity, the burden can shift to the person defending the Will. They may then need to establish that the deceased understood the nature and effect of the Will when it was signed.

Initial Burden on the Challenger

A person challenging the Will must first raise a genuine concern supported by evidence. They must be able to demonstrate circumstances which cast doubt on the validity of the document. Once credible evidence is produced, the court may require the party wanting to uphold the Will to respond.

Capacity Disputes

In cases involving testamentary capacity, while there’s benefit from the initial presumption of validity, if the challenger produces evidence raising real doubt that the deceased may have lacked capacity, the burden effectively shifts.

At that stage, the party defending the Will may need to prove that the deceased understood what they were doing when the document was signed.

Lack of Knowledge and Approval

A similar shift can occur in knowledge and approval cases where suspicious circumstances are found to exist, for example, questions may arise where:

Undue Influence Claims

Strong evidence is needed to prove undue influence. The burden generally remains with the person making the allegation throughout the case. The challenger must prove that pressure was exerted to the extent that the Will no longer reflected the deceased’s own wishes.

 Real World Findings

We carried out an analysis of our callers’ concerns regarding will disputes over a six-month period. Our findings indicated a primary red flag was a caller being suddenly and unexpectedly left out of a will.

In these cases, callers often only found out after their loved one’s death that they had been excluded from the Will. The analysis also showed that this was often paired with concerns over late-stage will changes and lack of capacity.

(To protect caller confidentiality and comply with data‑handling obligations, we do not publish or discuss individual circumstances.)

What Evidence Creates a Strong Will Challenge?

Assumptions and family disagreements are not evidence when contesting a will. The outcome of most Will disputes depends heavily on the quality of the evidence available, so strong and credible evidence is generally needed

1. Medical Records Near the Signing Date

Medical records remain among the most important pieces of evidence. Records created close to the date the Will was executed may reveal:

• Diagnosed cognitive conditions.
• Memory problems.
• Confusion or disorientation.
• Mental health concerns.
• Medication that may have affected decision-making.

2. The Solicitor’s File

The drafting solicitor’s file can also be extremely valuable because it should provide detailed insight into how the Will was prepared as well as any concerns raised. This should include:

• Attendance notes.
• Details of meetings.
• Instructions provided by the deceased.
• Capacity assessments.
• Correspondence relating to the Will.

3. Who Arranged the Solicitor?

The court may also closely examine the involvement of beneficiaries and issues raised may include:

• Did a beneficiary arrange the appointment?
• Did they transport the deceased to meetings?
• Were they present when instructions were given?
• Did they communicate with the solicitor on the deceased’s behalf?

4. Is the Will Significantly Different From Earlier Wills?

A Will that differs dramatically from earlier versions often attracts closer examination on surrounding circumstances, such as:

• Children are unexpectedly disinherited.
• A new friend receives a substantial inheritance.
• A carer becomes the primary beneficiary.
• Long-standing beneficiaries are removed without explanation.

5. Witness Evidence

The observations of witnesses may play an important role, such as providing insight into:

• The deceased’s appearance and behaviour.
• Signs of confusion or vulnerability.
• Whether the deceased appeared pressured.
• Conversations taking place during execution.

Protecting Your Position With a Caveat

If you suspect that a Will may be invalid, it is often important to act quickly. This is because once a Grant of Probate has been issued, the administration of the estate can move forward and assets may begin to be distributed. You can check on the Gov.UK Probate Search if probate has been granted.

One of the most effective early steps is entering a caveat at the Probate Registry. This prevents a Grant of Probate from being issued while it remains in force, giving time for concerns about the Will to be investigated.”

Speak to an Experienced Contentious Probate Solicitor

As will disputes are complex and the legal burden of proof can shift, it’s advisable to speak to a contentious probate solicitor as early as possible.

As a claims management company, we partner with a panel of contentious probate solicitors who are here to help with a free, initial consultation.

They offer a range of fee structures, including ‘No Win, No Fee’ for certain cases along with other flexible funding.

Contact our team on 0333 358 3034. Alternatively, complete our online contact form and we will call you back.