Mirror wills: what they cover and what they quietly miss

A solicitor sits across from a couple in their forties. They own a house, have two children from their current marriage, and want everything to pass simply between them. The solicitor drafts two wills: identical in structure, each leaving everything to the other, then equally to the children. Both sign. Both feel the matter is settled. It rarely is.

Mirror wills are the most common estate-planning instrument used by married couples in England and Wales, and for straightforward families in stable circumstances they do their job adequately. But the word mirror contains a quiet deception. A mirror shows you a reflection of now. It tells you nothing about what happens next.

What mirror wills actually do

Each spouse makes a separate will. The documents are not legally bound to each other; they simply happen to be symmetrical. On the first death, everything passes to the surviving spouse. On the second death, the estate passes to whoever the couple named, usually the children equally.

This works well when both spouses die without the family's circumstances changing. The problem is that most families change considerably between the signing of a will and the second death. Children grow up. Marriages break down. The surviving spouse remarries. Care costs mount. And the will, sitting in a drawer or a solicitor's filing cabinet, stays exactly as it was.

The most underappreciated risk is what practitioners sometimes call sideways disinheritance. When the first spouse dies, the survivor inherits everything outright. There is nothing legally to stop them from later changing their own will, remarrying, or simply spending the estate. If the survivor does remarry, that marriage automatically revokes their existing will under English law unless a new will is made in contemplation of that marriage. Their new spouse then acquires statutory rights to a share of the estate, and the children of the first marriage may receive nothing at all.

This is not a rare edge case. Second and third marriages are common among the demographic most likely to hold significant assets. The children who were named beneficiaries have no enforceable claim. Their inheritance depends entirely on the continued goodwill and good health of the surviving parent.

The three gaps most couples overlook

Beyond remarriage, there are two further exposures that mirror wills do not address.

The first is care-fee planning. If the surviving spouse requires residential care in later life, the local authority will assess their assets when determining what they must contribute. An estate inherited outright is an estate available to fund care. Some families assume that having a will protects wealth from this assessment; it does not. The assets belong to the survivor, and a will only speaks from death. Discretionary trusts, life interest trusts, or other structures within the will can offer some protection here, but these require deliberate drafting and are absent from most standard mirror wills. This is an area where specialist legal advice is important, because the rules around deprivation of assets are strict and the consequences of getting it wrong are serious.

The second gap is more practical and less discussed. A will is a legal document, not a record. It names beneficiaries and executors, but it does not tell those people where the assets are, what institutions hold them, what debts exist, or how to access the paperwork they will need. Executors in England and Wales must apply for a grant of probate before they can deal with most assets, and that process requires locating account details, valuations, property deeds, insurance policies and pension nominations. Most families discover, in grief, that this information is scattered across dozens of files, inboxes and memory. The will creates the legal framework; the evidence to make it work is often missing.

Pension nominations are a particular blind spot. Most workplace and personal pensions sit outside the estate entirely and are not governed by the will at all. They pass according to an expression of wishes lodged with the pension provider, which many people complete once and never review. A pension nomination made in a previous marriage, or before children were born, may distribute a significant asset in a direction the will does not anticipate.

None of this means mirror wills are wrong. For many couples they are the right starting point. But a will is a document, and a document is not a plan. A complete plan includes a lasting power of attorney for each spouse, reviewed pension nominations, a considered view on trust structures where the estate warrants it, and a clear record of where everything is held. That record needs to be accessible to the right people at the right moment, without requiring a search through a lifetime of paperwork.

The families who navigate probate with the least difficulty are those where someone, at some point, took the trouble to write it all down in one place.

Glenvault is built for exactly that purpose. You can begin organising your estate documents, will, nominations and asset records at glenvault.com/signup.