Definition
Mutual wills are separate wills made by two people (typically spouses) containing a legally binding agreement that prevents the survivor from changing their will after the first person dies.
Unlike ordinary wills that can be changed at any time, mutual wills create a contractual obligation between the testators. After the first death, the law imposes a constructive trust that enforces the original agreement, even if the survivor lives decades longer and circumstances change dramatically.
What Do Mutual Wills Mean?
Mutual wills are two separate wills (not a single joint document) made by individuals—typically spouses or civil partners—with a contractually binding agreement that neither will revoke or change their wills. The critical element is the contract itself. Matching or identical terms aren't enough. You must prove "clear and satisfactory evidence" of a legally enforceable agreement, as confirmed in Goodchild v Goodchild [1997]. This distinguishes mutual wills from mirror wills, which look identical but lack the binding agreement. The doctrine originated in the landmark case Dufour v Pereira (1769), where Lord Camden established that testators who die first "carry the agreement into execution" through their death.
When the first person dies, equity imposes a constructive trust on the survivor's estate. This means the survivor legally becomes a trustee of the agreement, not the absolute owner of their property. Even if the survivor writes a new will leaving everything to different beneficiaries, their executors must distribute the estate according to the original mutual wills agreement. The trust is sometimes called a "floating trust"—it exists from the first death but only crystallises (becomes fixed) when the survivor dies. Importantly, mutual wills are not revoked if the survivor remarries, unlike ordinary wills made before marriage. For example, James and Patricia, each with children from previous marriages, make mutual wills in 2016 leaving everything to each other on first death, then dividing equally among all four children. When James dies in 2018, Patricia legally cannot change her will to favour only her own children, even if she lives another 20 years and her relationship with James's children deteriorates completely.
Mutual wills were more common historically when couples died closer together in time and family structures were simpler. Today, the survivor may live 20-30 years after the first death, during which circumstances change dramatically. Financial emergencies, beneficiary relationship breakdowns, changes in tax law, and care needs cannot be addressed—the survivor remains bound. Legal uncertainty also exists about scope: Does the trust cover only assets owned at first death, or also assets acquired later? Can the survivor make lifetime gifts? According to HMRC guidance (Inheritance Tax Manual IHTM12063), determining what property is subject to the constructive trust can be difficult. Most solicitors actively discourage mutual wills. The preferred modern alternative is a life interest trust, which provides similar protection for blended families while allowing flexibility if circumstances change.
Common Questions
"Can I change my will after my spouse dies if we made mutual wills?" No. If you made genuine mutual wills with a binding contractual agreement, you cannot legally change your will after your spouse's death. Even if you write a new will, a constructive trust will ensure your estate is distributed according to the original mutual wills agreement. The law treats you as a trustee, not the absolute owner.
"What's the difference between mutual wills and mirror wills?" Mirror wills have identical or matching terms but no binding agreement between the couple. Each person remains free to change their will at any time, even after the other dies. Mutual wills include a contractual agreement that prevents changes after the first death. Mirror wills are flexible; mutual wills are legally binding and inflexible.
"Are mutual wills a good idea for blended families in second marriages?" While mutual wills can protect children from your first marriage, most solicitors advise against them due to extreme inflexibility. A life interest trust typically achieves the same goal—your new spouse can live in the family home and receive income, but your children's inheritance is protected—while allowing adjustments if circumstances change.
Common Misconceptions
Myth: If we both make wills with the same terms, they're automatically mutual wills.
Reality: Identical or matching wills (called mirror wills) are not mutual wills unless there's also a separate, contractually binding agreement between you that neither will change the wills. The agreement is the critical element, not the similar content. Many couples have mirror wills without realising they're still free to change them. The term "mutual" sounds like it just means "shared," but legally it requires a binding contract.
Myth: Mutual wills are the best way to protect my children's inheritance in a second marriage.
Reality: Most estate planning solicitors actively advise against mutual wills for second marriages, despite them seeming like an obvious solution. Life interest trusts offer the same protection—your new spouse is provided for during their lifetime, while your children's inheritance is preserved—but with flexibility to adjust if circumstances change. Mutual wills lock both of you into decisions that may become inappropriate decades later. The survivor might live 20-30 years, during which family relationships, financial circumstances, and needs can change dramatically.
Related Terms
Understanding Mutual Wills connects to these related concepts:
- Mirror Wills: Wills with matching terms but no binding agreement, leaving both parties free to change their wills at any time, including after the first death.
- Life Interest Trust: The preferred modern alternative that achieves similar goals to mutual wills for blended families but with significantly more flexibility and less risk of disputes.
- Revocation: The act of cancelling or changing a will, which the survivor cannot do after the first testator dies under a mutual wills agreement.
- Blended Family: The primary situation where mutual wills are considered, typically in second marriages where couples want to protect children from previous relationships.
Related Articles
- Article on blended family estate planning: Explores comprehensive strategies for protecting children's inheritance while providing for a new spouse, showing why trusts typically work better than mutual wills.
- Article on second marriage planning: Addresses the balance between providing for a new spouse and protecting children from previous marriages—the core dilemma that leads people to consider mutual wills.
- Article on life interest trusts: Explains the modern alternative that achieves mutual wills' protective goals with flexibility, showing why contemporary estate planning has moved away from mutual wills.
Need Help with Your Will?
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Legal Disclaimer: This glossary entry provides general information about mutual wills under English law and does not constitute legal advice. Mutual wills create complex legal obligations with serious long-term consequences. Before creating mutual wills or if you believe you are bound by a mutual wills agreement, consult a qualified solicitor specialising in estate planning or contentious probate.