Enforcing an agreement never to change wills

A Will is a document that can never truly be unchangeable. Even if a term in the Will stipulates that the will is irrevocable, that Will can still be revoked and can be changed at a future date.

But what if there was some form of agreement or promise, made to another, that the Will would never be changed? What if the promise prompted the other to make a Will in similar terms, in reliance on the assurance? What if that agreement was so serious that it would be unconscionable to allow one person to go back on that agreement, when the other one has relied upon it?

This creates a dilemma. On the one hand, the courts tend to protect people from the unconscionable acts of other people. On the other hand, legal rules stipulate that a person is free to change or revoke his Will whenever he likes.

The solution to this dilemma comes in the form of (what we call in the trade) “the equitable doctrine of Mutual Wills”.

Mutual wills

Mutual wills arise when 2 (or more) people make an agreement as to how their combined estate (or part of that estate) should be distributed after their respective deaths, and then further agree that those terms should be binding and never revoked.

If it can be demonstrated that such an agreement was reached, then the equitable doctrine of Mutual Wills creates a “Trust” (sorry – legal jargon) that binds the Will-makers. In a nutshell, a trust is a mechanism by which a person’s property is held or controlled in a specific manner until it can be provided to the person or people who are intended to benefit from that trust. In the case of Mutual Wills, the assets identified in the Will are held on trust until they can be provided to the intended beneficiary or beneficiaries of the Mutual Will. Even if a Will-maker changes the terms of the Will in the future, the assets that are subject to a trust will still be distributed in accordance with the terms of that trust, and not in accordance with the terms of the new Will.

Whilst this area of law is growing in popularity in recent times, with reported decisions on the subject matter becoming more frequent, the basic law was settled back in the 1700’s.

The typical case involves 2 people (although it is possible for mutual Wills to be created by more than 2 people) reaching an agreement as to how they wish to dispose of their assets after death. Usually, they provide their assets to each other in the first instance. That way, whichever one of them dies first passes all of their assets to the survivor. When the survivor subsequently passes away, the assets are then distributed to others in accordance with the agreement. Separately to this, the 2 Will-makers also make a serious binding agreement with one another that they will never change their Wills in the future.

Again, the typical case tends to involve parents or step-parents agreeing upon how to provide their estates to their children when they have both died.

The agreement tends to arise when each parent has different ideas about how the estate should be distributed, and they reach some form of compromise (given the fact that a Will can be changed at any time in the future) whereby they must rely upon the other to fulfil when they are no longer around to ensure for themselves.

For example, 2 people marry later in life. They have each been married before. They each bring their own assets to the new relationship. They each have children from their former relationships. They each desire to benefit their own individual children, and they suspect that their partner might not share the same desire. In order to guarantee that their own children benefit, both husband and wife make Wills in “mirror image terms” whereby the first to die passes all assets to the other spouse, who becomes responsible for distributing those assets equally amongst the children from both previous relationships after his or her own death. Then, to make sure that the terms of these mirror Wills are not changed after the first one dies, they make a binding agreement with one another that the Wills shall be irrevocable.

It is this binding agreement “never to revoke the Wills” that gives rise to the Mutual Will.

One would imagine that both Will-makers may have been inclined to make Wills in starkly different terms if the binding agreement was never reached. Each spouse relies upon the other never to change the terms of the Will if he/she becomes the one with the responsibility to make the final distribution.

Given the fact that a Will can always be revoked, even with such an agreement in place, the binding agreement gives rise to a trust. Whilst both Will-makers are still alive, the binding agreement can be brought to an end. If one party tells the other that they no longer wish to be bound by the agreement, then the deal is over and the corresponding spouse will have an opportunity to change the terms of his or her own Will to account for the frustration of their original intentions. However, if the Wills remain unchanged by the time the first party dies, thereafter that trust binds the survivor. Even if he or she subsequently changes the terms of the Will, the trust should prevent relevant assets from being passed to anybody other than the original intended beneficiaries.

The crucial ingredient to establish mutual Wills is the binding agreement never to revoke. Without such a binding agreement, no trust is created.

It is therefore not sufficient that the parties have produced Wills in mirror image terms. Something further is required.

It must be proven that the binding agreement was so serious that it amounts to a contract. If this cannot be proven, then it will not be possible to establish the necessary trust.


If you believe that you should benefit from the terms of a mutual Will, then you should concentrate on gathering the evidence to prove that the Will-makers agreed never to revoke the terms of their Wills. There should be an examination of the file of the will drafting solicitor, in case it contains references to the binding agreement. Those people who witnessed the signing of the Wills should be interviewed in case they were advised of the binding agreement. Family members and close friends should be questioned in case they were appraised of the situation by the Will-makers.