In a recent webinar for MBL, Trust and Probate Litigation associate Judith Swinhoe-Standen summarised a range of notable contentious probate cases recently decided by the courts of England and Wales. This article explores recent cases involving mutual wills.

Mutual wills are made by two people (usually a couple) in largely similar or identical terms, by which they agree that their wills are irrevocable without the other’s consent. Entering into mutual wills is tantamount to entering into a binding contract.


Mutual vs. mirror wills

Mutual wills are often confused with mirror wills. Mirror wills are also usually made by couples in identical terms, but the difference is that nothing is stopping one of them from changing their will in the future. Mirror wills are very common, in contrast to mutual wills.


Pitfalls of mutual wills

Couples might at first think that mutual wills would be a sensible idea as they could give piece of mind that the surviving spouse will not pass the family wealth to someone else under a new will.

However, there are significant disadvantages to mutual wills. First, they heavily restrict a surviving spouse’s choices. As they cannot validly revoke the mutual will, they are stuck with it for the rest of their life. They cannot add or remove any beneficiaries, which means they cannot accommodate relationships that change over time.

Disputes can also arise as to whether mutual wills were validly executed, particularly as to whether the agreement to do so was sufficiently clear and free from undue influence. Two recent cases illustrate this.


Agreement set aside: Naidoo v Barton

In Naidoo v Barton [2023] EWHC 500 (Ch), the claimant (C) and the first defendant (D) were two of seven children born to the deceased (W) and her husband (H). W and H had made wills in 1998, leaving their whole estates to each other and then to D after they had both died. They left nothing to their other children. Each will referred to the other and stated within them that they were “intended to be in law mutual wills”. H died in 1999.

In 2015, W made a new will appointing C as her sole executor and beneficiary. W died in 2016. C obtained a grant of probate for the 2015 will, but D denied its validity, arguing that the 1998 wills were binding because they were mutual wills. C sought an order pronouncing the validity of W’s 2015 will and rescinding any mutual wills agreement in respect of W’s estate.

There were four central issues in this case:

  1. Whether there was a mutual wills agreement in relation to the 1998 wills;
  2. Whether any such agreement was vitiated by a mistaken belief by H and W as to the consequences of the mutual wills agreement;
  3. Whether the test for undue influence in making mutual wills was (a) the test in Royal Bank of Scotland v Etridge (No 2) [2001] UKHL 44 or (b) the test for undue influence ordinarily applied in probate disputes; and
  4. Whether any mutual wills agreement had been procured by undue influence exercised by D.

Taking each of these issues in turn:

  1. The court was satisfied that there was a mutual wills agreement. The wills referred to each other and described themselves as mutual wills. W’s later will, therefore, did not revoke the mutual will.
  2. By extension, the court found that H and W had not been mistaken about the consequences of the mutual wills. They had known and understood the effect of entering into them in 1998, and they could have jointly revoked them before H died in 1999.
  3. Regarding the test for undue influence in these circumstances, the court considered whether to apply the testamentary or contractual test. In assessing whether a will has been procured as a result of undue influence, in testamentary proceedings the court will usually consider whether the testator was coerced into making the will in the terms in question. The Etridge test is ordinarily used in contractual situations and applies where there is a relationship of trust and confidence and a transaction that calls for an explanation. In those circumstances, there is a rebuttable presumption that undue influence has been exercised.

The court in Naidoo v Barton decided that the Etridge test should apply to mutual wills because they are binding contracts rather than testamentary dispositions. Therefore, the usual probate test for undue influence would not apply.

  1. In applying the Etridge test, the court found that D had exercised undue influence over his parents to induce them to enter the mutual wills. D had power of attorney over them both and had been running the family business for some time. When they made their wills, they were vulnerable, and H was seriously ill. Their affairs were complex and demanding, and both were under stress. The court found that their level of trust in D, and their dependency upon him, was “profound”.

The court also commented that the mutual wills being solely in D’s favour called for an explanation. It was evident that he was responsible for giving instructions that the wills be mutual, and he had achieved that by abusing his parents’ vulnerability and his influence upon them. He had not established that W had acted free of his undue influence and there was no evidence that either she or H had received any advice capable of ensuring their wish to enter into a mutual wills agreement was in the exercise of their own free will.

Despite the court finding that the contract to enter into mutual wills was valid, the mutual wills agreement was set aside.


Insufficient agreement: McLean v McLean

In McLean v McLean [2023] EWHC 1863 (Ch) was a case on appeal from the Central London County Court, the deceased (W) and her husband (H) made mirror wills in 2017, leaving their estates to each other if surviving and the residue to their four children in equal shares (three of which were H’s from his previous marriage (the appellants), one (Brett) was W’s). H died in 2019, and W inherited his estate. W made a new will in 2019, leaving her entire estate to Brett. She died shortly afterwards.

The appellants challenged W’s 2019 will on the basis that the 2017 wills were mutual wills and could not be revoked by W’s 2019 will. Although there had been no explicit agreement that the 2017 wills would be mutual wills, the relevant section of the attendance note taken by the solicitor who prepared them referred to H “trusting the wife implicitly” not to leave her entire estate to Brett if H predeceased her. As it happened, W did exactly that.

The court found that there was not a sufficiently clear agreement for the 2017 wills to count as mutual wills.

As an alternative argument, the appellants suggested that there were circumstances giving rise to proprietary estoppel: H relied on W’s assurance that she would not disinherit the appellants, and he acted to his detriment by executing the 2017 will. The judge noted that, for the estoppel claim to succeed, W must have made a representation that she would not revoke her will.

As the appellants had failed to establish a clear agreement to enter into mutual wills, the judge took this as “a short answer to the estoppel point” and decided it was unnecessary for him to consider whether any form of estoppel could be sufficient for establishing mutual wills. However, now that this idea has been floated, it will be interesting to see if it is run again in a future case.


Takeaway points

If testators wish to create mutual wills, it is advisable to make explicitly clear they are mutual wills to avoid disputes about their validity.

Solicitors advising on mutual wills should ensure they consider the Etridge test rather than the probate test for undue influence, and should take care to advise clients clearly on the practical consequences of mutual wills.

Above all, mutual wills are generally inadvisable to enter into. In making mutual wills, testators are effectively contracting out of the doctrine of testamentary freedom as they are unable to update their wills in the future without the other’s consent, which cannot be obtained if one of them has died.



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