Can a Will Be Challenged for Undue Influence or Fraudulent Calumny?

When most people think about challenging a Will, they usually think about capacity, paperwork, or whether it was signed properly.

But sometimes the real issue is much murkier than that.

Sometimes the problem is pressure. Sometimes it is manipulation. And sometimes it is one person quietly poisoning the testator’s mind against someone else.

That is where undue influence and fraudulent calumny come in.

They are closely linked, but they are not the same thing. Both can affect whether a Will truly reflects the testator’s wishes. Both are difficult to prove. And both are exactly why proper Will writing is about far more than just filling in a form.

What is undue influence?

In simple terms, undue influence is where someone pressures a person into making a Will, or changing a Will, in a way that does not genuinely reflect their own free wishes.

That does not mean every family disagreement counts. Families fall out. People argue. Adult children get pushy. Relatives have opinions. None of that, by itself, is enough.

The issue is when pressure crosses the line into coercion.

That might mean the testator feels frightened, worn down, dependent, or simply unable to say no. Sometimes it is a big dramatic fallout. More often, it is not. More often it is a slow, relentless drip of pressure until the person gives in for an easier life.

That is what makes these cases so difficult. Real coercion does not always look dramatic. Sometimes it just looks like exhaustion.

Why is undue influence so hard to prove?

Because the law sets the bar quite high.

There is no automatic presumption of undue influence in Will disputes. The person alleging it has to prove it. And of course, by the time the dispute reaches that stage, the one person who could clear it all up, the testator, has died.

That is why suspicion is not enough.

It is not enough that someone was elderly.

It is not enough that they were vulnerable.

It is not enough that one child was more involved than the others.

And it is not enough that the person benefiting happened to be forceful, loud, or a bit of a steamroller.

The court will look at the actual evidence, not just the family politics.

A recent case, Rea v Rea [2024], makes that point well. The court made it clear that vulnerability does not automatically mean someone is incapable of making their own decisions, and a strong personality does not automatically mean coercion.

That is the uncomfortable truth in these cases. Some Wills look unfair. Some family situations look suspicious. But looking suspicious and proving undue influence are two very different things.

What is fraudulent calumny?

Fraudulent calumny is different, although it often sits in the same sort of family mess.

This is where someone deliberately poisons the testator’s mind against another person, usually someone who would normally expect to inherit.

Put bluntly, it is when someone feeds the testator lies, or reckless allegations, in order to turn them against another beneficiary.

For example, one child tells a parent that their sibling is greedy, abusive, dishonest, neglectful, or only interested in money, when that is not true. The parent believes it, changes the Will, and cuts the other child out or reduces their share.

That is not just influence. That is deception.

And it can be incredibly damaging, because once those ideas take hold, the testator may think they are acting reasonably when in reality they are acting on false information.

What is the difference between the two?

The simplest way to look at it is this:

Undue influence is about pressure.

Fraudulent calumny is about lies.

One is coercion. The other is poisoning the mind. Sometimes the two overlap, but they are not interchangeable.

What should raise concern?

As Will writers, we are not there to investigate families like some sort of probate detective agency. But we absolutely should be alert to red flags.

Things that can ring alarm bells include:

• someone insisting on being present throughout the meeting
• someone speaking over the client or answering for them
• a client seeming nervous, hesitant, or overly keen to please
• sudden major changes from an earlier Will
• exclusion of a close family member where the explanation does not really stack up
• instructions that sound rehearsed or borrowed
• reasoning that focuses heavily on what one person has said about another, rather than the client’s own direct experience

Now, none of those things automatically mean undue influence or fraudulent calumny is happening. But they are signs to slow down, ask proper questions, and make sure the instructions are genuinely the client’s own.

What can be done about it?

First and foremost, see the client on their own wherever possible.

That is not just best practice, it is common sense. If someone else is constantly hovering, interrupting, or steering the conversation, you are never really getting clean instructions.

It is also important to build trust with the client. They need to know that you are there to advise them, not rush them, not pressure them, and not let a domineering relative hijack the process.

Where a client is excluding someone, or leaving things in a way that is very different from what might ordinarily be expected, it is worth exploring the reasons properly.

Are they speaking from their own experience?

Or are they repeating a story that someone else has fed them?

That distinction matters.

And as ever, detailed attendance notes matter enormously. Not vague scribbles. Proper, comprehensive notes. Notes that would stand up if you ever had to justify the circumstances later. That is where Larke v Nugus comes in, and why good file notes are not optional.

They can make the difference between a defensible Will and a full-blown courtroom bunfight.

Why this matters so much

The truth is, you cannot always stop a family dispute.

You cannot stop resentment.

You cannot stop greed.

And you certainly cannot stop people turning strange when money is involved. Estates have a remarkable ability to bring out sides of people that should probably stay locked in the attic.

But what you can do is make sure the Will writing process is robust.

That means proper questioning, proper privacy, proper records, and proper professional judgement.

A Will should reflect the wishes of the person making it, not the agenda of the loudest, strongest, or most manipulative person in the room.

Final thought

Not every unequal Will is suspicious.

Not every difficult child is coercive.

Not every exclusion is caused by manipulation.

But when something feels off, it is worth paying attention.

Because once the testator has died, the question is no longer what they meant to do. The question is what can be proved.

And that is exactly why careful Will writing matters.