The Doctrine of ‘Mutual Wills’ – McLean v McLean

8th August 2023

The doctrine of ‘mutual wills’ is a rarely used, unique and yet incredibly powerful tool in the world of probate. We explore the High Court’s recent decision exploring the topic, including its potential applicability in estoppel claims.

The doctrine of 'mutual wills' – irrevocability is key

It is commonplace for testators, usually spouses or partners, to agree to adopt the same distribution terms in their wills – so-called ‘mirror wills’. ‘Mutual wills’ go one, very significant, step further, in that the parties agree that neither party will alter or revoke either will after the death of the first testator.

Agreement and irrevocability are key. In effect, there is a contract between the two parties that the terms of the wills are binding and cannot be amended unilaterally after the death of the first testator. Clear and unequivocal evidence of this binding mutual intention is required – a mere understanding or expectation will not be sufficient. In some instances, testators may choose to complete a single joint will, although this isn’t necessarily required, and an express clause could be included in their respective wills instead.

Where a surviving party amends their mutual will after the first death, the executors of the new will would hold the deceased’s estate on trust for the beneficiaries of the original mutual will – i.e. the terms of the mutual will would still prevail despite the later amendments.

McLean v McLean [2023] EWHC 1863

The High Court recently ruled on an appeal case where the doctrine of mutual wills was central. The claimants were the three children of Reginald McLean and his first wife. The defendant was the son of Reginald and his second wife of 45 years, Maureen.

Reginald and Maureen executed mirror wills in June 2017 (the ‘2017 Wills’), leaving their estates to each other as survivors, and the residuary estate of the surviving spouse to their children (the claimants and defendant) in equal shares. Following Reginald’s death in March 2019, Maureen executed a new will that August, revoking her 2017 Will and leaving her entire estate to her son, the defendant. Maureen then sadly died a couple of weeks later.

When drafting the 2017 Wills, Maureen stated that she would not change her will or disinherit her stepchildren (the claimants) and that she trusted Reginald implicitly. Reginald was advised that there was no guarantee that Maureen would not later change her will. Reginald acknowledged this and stated he too trusted her implicitly. The specific issue of mutual wills was not expressly discussed, although Reginald and Maureen did not contemplate a situation where either of them would change their wills.

Reginald and Maureen wrote a heartfelt joint letter to the four children in 2018, explaining the existence of the 2017 Wills, that each child would get “something to enjoy”, that they were “very happy” with the contents and that they “wouldn’t feel confident to change anything” now due to their deteriorating health.

It was argued by the claimants that the implicit trust exhibited by Reginald and Maureen in drafting the 2017 Wills, together with the joint letter, demonstrated a mutual agreement that neither of them would unilaterally revoke their will.

The court however disagreed; instead finding that they had not entered a legally binding agreement not to revoke, rather they had both simply opted into a moral obligation to each other, which was inadequate to create mutual wills. The fact that Reginald and Maureen had a common intention to provide for all four children in 2017 did not mean that they promised never to revoke the 2017 Wills.

The court also explored whether, in circumstances stopping short of binding mutual agreement, the doctrine of mutual wills could be extended to allow an estoppel argument to succeed. Here, such an argument would be that Maureen made a representation (not to later amend or revoke her will), that she intended to be legally binding, that Reginald acted on to his detriment (by executing his will). The court found however that this argument, again, was not founded on the facts. It was merely the implicit trust of two loving spouses, stopping short of the high threshold required to establish a legal obligation not to revoke the 2017 Wills.

The court therefore reaffirmed the existing case law position. It did however tease that an estoppel-based argument may have some plausibility should the right fact-pattern arise:

“At least as a matter of principle, it is not easy to see why an estoppel should not operate in the realms of mutual wills if the evidence were clear enough […] Mutual wills operates in the realms of equity in order to prevent injustice, and that is what estoppels do as well”. [para 42]

Key takeaways

While mutual wills provide certainty of provision after death, which can be appealing in some circumstances, they bring an inherent lack of flexibility and testamentary freedom if family or financial circumstances do change, particularly if there is a long time between the testators’ respective deaths. For this reason, they are not routinely recommended and setting up trusts to create a life interests may strike a better balance.

We would always recommend getting a will professionally drafted. For further information on mutual wills and will drafting generally, please get in touch with our Succession & Tax team. If you are potentially looking to contend or defend a will, please get in touch with Thomas Middlehurst in our Contentious Trusts & Estates team.

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