Mutual wills: can undue influence be considered?

read time: 2 min

It has been settled law since the late 1800s that there is no presumption of undue influence in relation to wills. A claim of undue influence in the making of a will requires proof of actual undue influence, i.e. that the testator has been coerced into making a will that he or she does not want to make. 

In contrast, lifetime transactions and contracts can be set aside on the basis of presumed undue influence, also known as the Etridge test. This can arise where:

  • A pre-existing relationship of influence exists between the testator and potential offending party.
  • The transaction is without logic given the relationship between the parties, such that it calls for an explanation.

So, what is the correct test where, during a testator’s lifetime, he or she enters into a contract to make mutual wills? In this article, we investigate the claim in the recent case of Naidoo v Barton.

The facts

In 1998 the deceased and her husband made wills leaving everything to each other in the first instance, and upon both of their deaths to just one of their seven children, a son of the marriage. The wills stated their intention to be mutual wills. The husband died in 1999. 

In 2015 the deceased made a new will appointing the claimant, another child of the marriage, as sole executor and beneficiary. The deceased died in 2016. 

The son, original beneficiary under the 1998 wills, disputed the 2015 will's validity, arguing the mutual wills were binding from 1998.


The Etridge test was to be applied, not the probate test as a mutual will agreement was a contract and, even if it was set out in the wills, it was not a testamentary provision. 

When the 1998 wills were made, both the deceased and her husband were vulnerable owing to illness and the complexity of their affairs which caused stress to them both. The son held full power of attorney over both to deal in their affairs. Their trust and reliance upon the son was clear such that the only proper inference was that he was responsible for the instruction of the mutual wills as he was the only beneficiary, with no benefit to the couple’s other children. 

The mutual wills agreement was rescinded as a result of the son’s undue influence and the court pronounced in favour of the validity of the 2015 will. 

What can we take away from this?

This decision puts beyond doubt the test to apply when considering undue influence in the making of a mutual wills agreement.

For more information, please contact the wills and inheritance disputes team.

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