What Impacts the Success Rate of Contesting a Will in the UK?

Contesting a will can be seen as an uncertain and complex course of action, however, in reality, the success rate of contesting a will in the UK depends on a clear set of legal and practical factors. From the strength of the legal grounds and quality of evidence, to timing, relationships, and strategic decision-making, each element can significantly influence the outcome.

In this guide, we explore what impacts the prospects of success in will disputes. Whether you are considering bringing a claim or defending one, understanding how courts assess validity challenges, such as lack of capacity, undue influence, or improper execution, can help you make informed decisions..

Advice for claimants

Are there legal grounds that give a claim the best chance of success?

Whilst all challenges require evidence, capacity claims are usually the most successful, subject to there being the necessary evidence both in the medical records, and first-hand evidence from those who had regular interactions with the testator.

The UK is an ageing population and with more and more people affected by dementia, this in turn will affect testators giving instructions for their will.

Due execution can also be a particularly successful challenge as the will may not be validly executed in accordance with the Wills Act 1837, particularly when the testator drafted the will or one of the beneficiaries drafted this for them.

In comparison, undue influence and fraudulent calumny are usually the most difficult challenges given the burden of proof.

Re Edwards 2007 confirmed that ‘mere persuasion’ is not enough to constitute undue influence, and that there must be some coercion or fraud involved which influenced the testator’s decisions.

How does timing affect the likelihood of success?

Do delays weaken a claim?

Early action is always advisable. Whilst a grant of probate can be set aside, if an estate has been distributed then steps will need to be taken to reclaim the assets.

In addition, whilst not a validity dispute, claims under the Inheritance (Provision for Family and Dependants) Act 1975 have a strict time limit of 6 months from the grant.

Delays may also affect the availability of documentary evidence and the willingness of parties to provide statements in support of the claim.

Does a claim by a spouse or financial dependant carry more weight in a claim?

Usually, yes. In capacity claims for example, medical evidence will only take you so far. Parties seeking to dispute the validity of the will need to give first-hand evidence of the testator's capacity and behaviour to support the challenge.

In addition, if undue influence is being alleged or fraudulent calumny, then the witnesses will be required to provide detailed evidence of why they believe the testator was being influenced and give examples of behaviours witnessed and discussions they have had with the testator.

As set out, suspicion is not enough. If they did not have a relationship with the testator, then they may not be able to provide this information.

What evidence can impact the success rate of contesting a will in the UK?

In a capacity claim, medical evidence can prove essential. If the testator attended their doctor with memory issues or had been diagnosed with dementia, this could be used in part to show that the testator lacked capacity.

As capacity fluctuates however, a diagnosis of dementia is not definitive evidence that the testator lacked capacity. 

The case of Parker v Felgate sets out that whilst a testator may subsequently lack capacity when the will is executed, providing they had capacity when instructions for the will were given and the testator knew what they were signing was the will they had given instructions for, the will is likely to be valid.

Does the size of the claim matter?

Can complex estates make a successful outcome more likely?

Yes. If an estate is complex or high value, then similar arguments to those raised when seeking to set aside the will may apply.

The testator may be elderly and suffering with dementia and may not have understood the complex structure of the tax planning measures they have undertaken or the extent of their estate, which is a capacity consideration under the Golden Rule in Banks V Goodfellow. It may also be that the testator drafted the will themselves and did not appreciate how their assets were held.

How can legal strategy improve your chances?

A well thought out legal strategy with the supporting evidence can be the difference between a will being set aside and a will being valid. Whilst parties may consider that the testator lacked capacity, the solicitor dealing with the case will be able to take an objective view of the medical evidence and supporting witness statements.

Should you choose settlement or litigation?

Settlement is always better than litigation. Litigation can be costly and time consuming. Whereas settlement by way of mediation for instance allows parties to be much more creative with how any settlement is structured.

Minimising the Risk of a Successful Will Challenge

Can a well drafted will still lose a claim?

No will is bulletproof. However, a well-drafted will with a letter of wishes explaining the reasoning for the legacies and any exclusion can be used as evidence of the testator's intentions.

In addition, detailed attendance notes by the solicitor who drafted the will can be invaluable in setting out the reasons as to why the solicitor considered the testator to have capacity. They should also detail who arranged and attended the appointments, as this can be a key consideration in undue influence claims.

How should you respond to a will dispute?

An executor ought to remain neutral in estate disputes or they may risk cost orders.

How does gathering evidence early strengthen a defence?

A beneficiary seeking to defend a claim should obtain the testator's medical records when capacity is in question. In addition, they should speak to those who had regular interactions with the testator to discuss if they had any concerns. It may be that the testator was suffering with memory issues, yet they did not seek medical intervention.

As mentioned above, the solicitors' file can provide key evidence which can strengthen the defence.

Is a long period of estrangement a strong defence?

Whilst is it not necessarily a strong defence, estrangement between the claimant and the testator may weaken their claim. Whilst medical evidence can take matters so far, first-hand evidence of the claimant's experience with the testator is invaluable.

If the claimant cannot show the concerns that they had, how can they show that the will is invalid and ought to be set aside?

Speak to a Solicitor about contesting a Will

For both claimants and defendants, early action and a carefully considered legal approach are critical. From securing key evidence to exploring settlement opportunities, the right strategy can protect your position and maximise the likelihood of a favourable outcome.

Our Contentious Trust & Probate solicitors take a partner-led, strategic approach to contentious probate matters, providing clear, objective advice tailored to even the most complex or high-value estates.

If you are considering contesting a will, or need to defend a claim, seeking early specialist advice can be decisive in achieving the outcome you require.

Contact Our Solicitors