Problems with Mirror Wills UK (2026): Can the Survivor Change Their Will After the First Death?

Mirror wills are two separate wills made by a couple — usually spouses or civil partners — that reflect each other in structure. Each will typically says: 'I leave everything to my partner, but if my partner predeceases me, I leave everything to [the same named beneficiaries, usually children].' They are called 'mirror' wills because each reflects the other. The critical legal point: (1) MIRROR WILLS ARE SEPARATE LEGAL DOCUMENTS: each will is entirely independent. They are not a joint document, not a contract, and not a legally binding arrangement. They happen to say the same thing — but that is a matter of coincidence at the moment of making them, not a legal obligation; (2) THE SURVIVOR IS COMPLETELY FREE TO CHANGE THEIR WILL: once the first partner dies, the surviving partner inherits the estate under the first partner's will (as intended). At that point, the surviving partner is free to: (a) revoke their existing mirror will entirely; (b) make a completely new will; (c) change all the beneficiaries; (d) leave everything to a new partner, new family, charities, or anyone else; (e) cut out the children from the first relationship; (3) THERE IS NO LEGAL OBLIGATION: the surviving partner made no legal promise when the mirror wills were drawn up. A solicitor who drafts mirror wills does not create any binding obligation between the spouses — they simply document what each person wants at that point in time. The will-making process creates no contract; (4) MOST FAMILIES DO NOT REALISE THIS: a very common misconception is that mirror wills protect the children — 'because we've both agreed to leave things to the kids'. That agreement is not legally enforceable. The surviving partner can change their mind completely the day after the funeral. Without structural protection built into the will itself, children's inheritance has no legal protection once assets pass to the surviving partner; (5) THE PRACTICAL CONSEQUENCE: the most common scenario where mirror wills fail: a widower inherits everything from his wife's estate under their mirror wills. He remarries. His marriage automatically revokes his existing will (Wills Act 1837 s.18). If he dies without a new will, his estate passes under intestacy to his new wife — the children from his first marriage receive nothing. Even if he makes a new will, it may benefit the new wife and her family entirely.

Mutual wills are a specific legal doctrine that can prevent the surviving partner from changing their will. Unlike mirror wills, mutual wills create a legally binding obligation: (1) WHAT ARE MUTUAL WILLS: mutual wills are wills made pursuant to a LEGALLY BINDING AGREEMENT between two people that neither will revoke their will after the first death. The key distinction from mirror wills: there is an express agreement — a contract — not to revoke; (2) HOW THE DOCTRINE WORKS: when both testators have made wills pursuant to the agreement, and the first testator dies, a CONSTRUCTIVE TRUST arises over the surviving testator's estate. The survivor holds their estate as a constructive trustee for the agreed beneficiaries. They cannot, in conscience, dispose of the trust property away from those beneficiaries — because equity treats them as holding it on trust for the very beneficiaries the agreement was made to protect; (3) THE EFFECT ON THE SURVIVOR: (a) the survivor can still spend their income, enjoy the estate, and manage their assets; (b) they can still make a new will — but the new will is caught by the constructive trust; (c) the new will does not release the trust obligation — the agreed beneficiaries can trace their claim; (d) if the survivor disposes of assets during their lifetime (to frustrate the trust), the recipients may be personally accountable; (4) WHAT IS REQUIRED FOR MUTUAL WILLS: (a) an express agreement between the testators not to revoke — ideally in writing, but it can be evidenced by conduct and surrounding circumstances; (b) the first testator must have died relying on the agreement (consideration); (c) the wills must have been made in pursuance of the agreement. Without these elements, the mutual wills doctrine does not arise; (5) THE PROBLEMS WITH MUTUAL WILLS: (a) inflexibility — the survivor cannot adapt their will to changed circumstances (a beneficiary dies; becomes estranged; needs financial support in a different way); (b) the agreement may be hard to evidence; (c) the survivor may remarry, acquire new children, or face completely changed family circumstances; (d) for these reasons, mutual wills are rarely the right solution in practice — the life interest trust is almost always preferable.

Mirror wills are particularly problematic in second marriages, blended families, and cases where one partner has children from a previous relationship: (1) THE CLASSIC SCENARIO: a couple in their second marriage each makes a mirror will. Between them they have: his children (from his first marriage) and her children (from her first marriage). Their mirror wills say: everything to each other; then split equally between all the children. They both intend their children to be protected; (2) WHAT ACTUALLY HAPPENS ON THE FIRST DEATH: the surviving spouse inherits everything from the first will. At that point, the surviving spouse owns the combined estate — including the share of the deceased spouse's estate. The deceased's children have no legal claim. The surviving spouse's obligation to the step-children is moral, not legal; (3) THE RELATIONSHIP CHANGES: if the surviving spouse remarries, their new will or intestacy may benefit the new partner — cutting out both sets of children. Marriage revokes any existing will automatically (WA 1837 s.18), and the new will or intestacy benefits the new family. The children from both first marriages are left with nothing; (4) THE SECOND MARRIAGE ITSELF IS THE TRIGGER: in England and Wales, marriage automatically revokes any will previously made by either party unless the will was made 'in contemplation of marriage' (WA 1837 s.18 — the will must expressly state that it is made in contemplation of the specific marriage). A mirror will made before a second marriage that does not contain this clause is automatically revoked on remarriage — meaning the person dies intestate or relies on a new will that may not protect the first family's children; (5) COHABITING COUPLES: for cohabiting couples (not married, not civil partners), mirror wills provide even weaker protection. Each partner's mirror will can be changed at any time. Neither partner has any automatic inheritance right under intestacy. If one partner dies and the survivor inherits everything, then the surviving partner decides to leave their estate elsewhere, the first partner's family receives nothing. The only protection is structural: trusts in the will itself.

The most effective way to protect children's inheritance is to build structural protection into the will itself — not to rely on a moral expectation: (1) LIFE INTEREST TRUST (PROPERTY PROTECTION TRUST): the most widely used solution. On the first death, the deceased's share of the estate (or the family home specifically) is NOT left outright to the surviving spouse — instead it is held on trust for the surviving spouse for life (right to live in the home and receive income), with the capital passing to the children on the second death. Structure: (a) the couple must hold the home as tenants in common (so each has a distinct share to leave by will — sever the joint tenancy if currently joint tenants); (b) the first will creates the trust with the surviving spouse as life tenant; (c) the children are named remaindermen; (d) the surviving spouse can live in the property and receive income but cannot give away or sell the capital; (e) even if the survivor remarries or makes a new will, the trust capital is protected for the named children; (2) IHT TREATMENT OF THE LIFE INTEREST TRUST: an IPDI (immediate post-death interest) qualifies for the spouse exemption at the first death (IHTA s.18). The trust capital is in the life tenant's estate for IHT at the second death (IHTA s.49(1)) — RNRB and TNRB available. This is as IHT-efficient as an outright gift to the spouse; (3) TESTAMENTARY DISCRETIONARY TRUST: an alternative structure leaves the estate to a discretionary trust for a class of beneficiaries (including the surviving spouse AND the children). The trustees decide how to distribute income and capital. More flexible than a life interest trust; more complex to administer. Can benefit the surviving spouse without giving them outright ownership; (4) NUPTIAL AGREEMENTS / COHABITATION AGREEMENTS: for second marriages or cohabiting couples, a pre-nuptial agreement or cohabitation agreement can specify what happens to assets on death or separation — but these are separate legal documents and work alongside the will, not as a substitute; (5) REGULAR WILL REVIEW: even with mirror wills (as a starting point), couples should review their wills: on any significant change (remarriage; new child; major change in assets; death of a named beneficiary); at least every 5 years. If trust structures are not wanted, at least consider whether specific legacies to children should be made in the first will to ensure direct inheritance.

Marriage (or the formation of a civil partnership) automatically revokes any will made before the marriage unless the will contains a specific saving provision: (1) THE REVOCATION RULE (WILLS ACT 1837 s.18): any will made by a person before they marry is automatically revoked upon the marriage. This rule is absolute — it does not matter that the parties intended the will to survive the marriage. A mirror will made before a second marriage, unless it expressly states that it is made 'in contemplation of' that specific marriage, is automatically revoked on the day of the marriage; (2) 'IN CONTEMPLATION OF MARRIAGE' SAVING: a will can be made in contemplation of a specific marriage and survive the marriage. The will must specifically state this — for example: 'This will is made in contemplation of my marriage to [full name] and shall not be revoked by that marriage.' Generic statements do not suffice — it must name the specific person to be married. After marriage, the will remains valid; (3) EFFECT OF REVOCATION: if the person's will is revoked by remarriage and they die without making a new will, they die intestate — their estate passes under the intestacy rules. For a remarried person: if they die leaving a spouse and children: the surviving new spouse receives the statutory legacy (£322,000 in 2024; indexed) plus half the residue; the children share the other half. Children from a first marriage share equally with children from the second marriage — but the new spouse's statutory legacy significantly reduces what the children receive; (4) IF A NEW WILL IS MADE: if the remarried person makes a new will after the marriage, that will is entirely their own document — the mirror structure of the earlier will is gone. The new will may or may not benefit the children from the first marriage. There is no obligation to include them; (5) WHAT COUPLES SHOULD DO: (a) after any marriage (first or subsequent), review the will immediately; (b) if using mirror wills as a starting point, include a 'in contemplation of marriage' clause if preparing the will just before a marriage; (c) better still: use the life interest trust structure from the outset to protect both sets of children structurally — regardless of what the surviving partner later does with their own will.