Mutual will disputes

Mutual will disputes and the law

Mutual will disputes can be extremely complex and require specialist legal advice.To find out where you stand contact our free legal helpline on 0333 888 0407 or send an email to us at [email protected]


The doctrine of “Mutual Wills” is often confused with the term “Mirror Wills”. Mutual Wills and Mirror Wills are fundamentally different legal concepts and the consequences of mixing the two up can be far reaching.

A Mirror Will is simply a Will that “mirrors” another Will, generally made by a spouse or partner, with terms that are similar and complimentary. For example, a wife might make a Will leaving everything to her husband if he survives her, but if he predeceases then on her death everything is to be divided equally between their children. The husband’s Mirror Will would then leave everything to his wife if she survives him and if she predeceases then on his death everything is to be divided equally between the children. Each Will mirrors the other, but crucially both parties are free at any time to revoke the Will and make another one specifying something quite different.

A Mutual Will on the other hand creates a binding agreement between the two parties which prevents the survivor from changing their Will and disposing of the estate in a different way.


The law on Mutual Wills is highly complex and we would recommend that professional advice be sought on a case by case basis.

However, the key requirement is that there must be evidence of binding intention between the parties that:-

  • Their estate is to be distributed in a particular way
  • The Wills cannot be revoked unilaterally.

The doctrine of Mutual Wills is in fact based on a legal fiction. A person is always at liberty to revoke their Will; Mutual Will or not. However, because there is a binding intention between the parties, the law of equity will step in and require the survivor to give effect to the agreement enshrined in the Mutual Will. Any attempted revocation becomes neutralised because the law, in effect, creates a trust over the survivor’s assets.

Because a Mutual Will binds the survivor in this way, the courts require a very high degree of proof that there was an agreement between the parties that the Wills were intended to be incapable of revocation. The courts have specified that the evidence required to prove an agreement not to revoke Mutual Wills must be “certain and unequivocal” , “clear and satisfactory”. A mere understanding between the parties as to how the survivor is to leave the property after the death of the first party is not enough. There must be evidence that the survivor had agreed not revoke the Will and for this reason Mutual Wills invariably include an express clause confirming that such a binding agreement exists. In the case of Charles v Fraser [2010] EW HC Civ (Ch) 2154, the court confirmed that it was good practice to set out the terms of the agreement within the Wills.

There are additional formalities relating to land. Under the Law of Property (Miscellaneous Provisions) Act 1989 the parties are required to sign a written agreement in order for the Mutual Wills to be effective, where those Wills specifically refer to the property or land.

Mirror Wills by contrast do not have to comply with any extra formalities and will be valid so long as they are made and executed in accordance with the Wills Act.


The trust created by the Mutual Will crystallises on the death of the survivor. Until then the survivor still has control over the assets, but they are restricted in what they can do with them. In particular, the survivor cannot act with the intention of defeating the agreement. This means that they cannot spend the assets or give them away if it is calculated to defeat the trust and prevent the ultimate beneficiary from benefitting.


Mutual Wills are relatively uncommon and most solicitors do not routinely recommend them to their clients.

The law is still unclear about how Mutual Will trusts operate in certain respects and the potential for litigation is significant.

Mutual Wills are also inflexible. Once entered into, they cannot be set aside unilaterally. This restricts the testamentary freedom of the parties and can lead to unforeseen and often upsetting consequences for the survivor.

Many people struggle to fully understand the principles of Mutual Wills and solicitors must exercise great care when explaining the concept to clients.

Mirror Wills by contrast are easy to understand and simple to follow. The chief drawback however with a Mirror Will is that the survivor is always free to revoke the Will and make a fresh one. In our experience this can cause disputes within families, especially where the survivor remarries and the children of the first marriage are not adequately provided for in the survivor’s new Will.

The most common scenario we encounter is where the survivor remarries and makes a new Will in favour of the new husband or wife who then goes on to outlive the testator, leaving the estate to their own children of a previous marriage.

How we can help with mutual will disputes

If you require guidance on mutual will disputes then you can call our free legal helpline on 0333 888 0407 or send brief details to us by email at [email protected]