Making a Will as a couple feels straightforward. You leave everything to each other, then to your children. But there is a question many couples never think to ask and the answer can have far-reaching consequences.
Are you making Mirror Wills or Mutual Wills? The two terms are often used as if they mean the same thing. They do not. Mirror Wills are the most common type made by couples in the UK, yet many people who have one don’t fully understand what it does and does not guarantee. Confusing them has led to contested estates, family disputes, and in some cases, claims against the solicitors who drafted them.
Mirror Wills: flexible, but not guaranteed
Mirror Wills are two separate Wills made by a couple, usually spouses, civil partners, or cohabiting partners, that reflect one another’s wishes. Typically, each partner leaves their estate to the other, and on the second death, the estate passes to agreed beneficiaries such as children.
Crucially, Mirror Wills are entirely independent documents. Either partner is free to change or revoke their Will at any time without telling the other. After the first death, the surviving partner could legally leave the estate to a new spouse, different children, or anyone they choose.
For many couples, this is never a problem. But for those in second marriages or blended families, where children from previous relationships are involved, it is a risk that deserves serious consideration.
Mutual Wills: binding, but inflexible
Mutual Wills look very similar, but carry a fundamentally different legal effect – both parties agree that neither will change their Will after the first death. That agreement forms a binding contract.
If the surviving partner makes a new Will in breach of that contract, the courts can intervene. In the case of Legg v Burton, a wife who progressively reduced her daughters’ inheritance through a series of new Wills was ultimately overruled, the original arrangement was enforced by the court.
However, most solicitors caution against Mutual Wills precisely because of their rigidity. Life changes. Families grow. Financial circumstances shift. A Mutual Will made today could create real hardship decades later, with no way to adapt.
Inheritance disputes
The gap between what a couple intended and what their Wills actually achieve is where inheritance disputes are born. When one partner dies and the other changes their Will, particularly following a remarriage, the resulting family conflict can be deeply damaging and expensive to resolve.
Disputes over whether Mirror Wills were intended to be mutually binding are a recurring feature of contested probate cases. The evidential challenge is significant: verbal agreements, however sincere, are notoriously difficult to establish in court. By the time a family seeks legal advice, the options are often limited and the costs are already mounting.
The risk does not end there
Many people focus on the risk posed by a surviving partner rewriting their Will. But the problem can travel further down the line than most families realise.
If a child inherits from you and later dies, their spouse may receive everything. If that spouse then remarries, your estate could ultimately end up benefiting an entirely different family, potentially someone else’s grandchildren rather than your own. The original intentions of the couple who made those Mirror Wills could be unravelled entirely, not through any bad faith, but simply through the passage of time and the ordinary events of life.
This is why it is worth thinking carefully not just about who inherits, but how, and whether the legal structure around your Will genuinely protects your wishes through more than one generation.
When family law and Will planning overlap
Will planning rarely exists in isolation. For anyone going through a divorce or separation, entering a new relationship, or navigating a blended family, the question of how your estate is structured sits at the intersection of family law and estate planning, and getting advice from one without the other can leave gaps.
A Will drafted before a divorce, or before a new partner came into the picture, may no longer reflect your intentions or adequately protect the people you care about most. Our Family Law team regularly works alongside our Wills and Estate Planning solicitors to ensure that any Will accurately reflects a client’s family circumstances at that point in time and is built to protect them if things change.
Professional negligence
This is not just a concern for families. Solicitors who draft Wills without clearly explaining the difference between Mirror and Mutual Wills, and the protections available, can find themselves exposed to professional negligence claims further down the line. A failure to advise on the risks, or to properly document that a Will is or is not intended to be mutual, can have serious professional consequences.
Clear, thorough advice at the drafting stage is the most effective protection for everyone involved.
What is the right approach?
For many couples, the answer lies not in choosing between Mirror or Mutual Wills, but in using trust provisions to achieve the right balance. A life interest Trust, for example, can protect the inheritance rights of children from a previous relationship while still allowing a surviving partner to benefit from the estate during their lifetime without the inflexibility of a Mutual Will.
Others prefer a more direct route: ring-fencing certain assets by leaving a share of a property or specific investments straight to children, while allowing the surviving partner use of or income from those assets. This approach does not suit every situation, but for some families it offers a simpler way of ensuring that key assets reach the right people.
The right solution will always depend on individual circumstances. Our Wills and Probate, Family Law, and Contentious Probate teams closely work together to ensure that client wishes are clearly documented, legally sound, and genuinely protected.
Get In Touch
John Gorner is a Consultant Solicitor in our Contentious Probate team. He specialises in contentious probate and trusts, residential property disputes, contentious Court of Protection, community care law (including safeguarding), public law/regulatory matters.
If you would like to speak with John or another member of our Contentious Probate team about the above topic, or any other related investigation, please call 0330 111 3131 or complete our online contact form.
