Mirror Wills UK: A Simple Guide

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Planning for the future is one of the most important things you can do for your family. And when you’re part of a couple, that planning often happens together. You’ve likely discussed pensions, savings, and maybe even what you’d do with a lottery win. But have you talked about what happens when one of you is no longer around?

It’s not a cheerful topic, but it’s a vital one. This is where making a Will comes in. For many couples in the UK, Mirror Wills are the go-to option. They seem simple, sensible, and fair. But like most things in life, there’s a bit more to them than meets the eye.

This guide will walk you through everything. We’ll break down what Mirror Wills are in plain English, explore who they’re for, and uncover the hidden risks you need to know about. Think of this as a friendly chat with a knowledgeable expert, designed to give you the confidence to make the right choices for you and your loved ones.

What Exactly Are Mirror Wills? A Simple Breakdown

Let’s start with the basics.

A Mirror Will is one of two separate legal documents made by a couple. Each person has their own Will, but the contents of both are either identical or very, very similar—they “mirror” each other.

Imagine a married couple, David and Sarah.

David’s Will says: “When I pass away, I leave everything I own to my wife, Sarah. If Sarah has already passed away before me, then everything goes to our two children, Emily and Tom, in equal shares.”
Sarah’s Will says: “When I pass away, I leave everything I own to my husband, David. If David has already passed away before me, then everything goes to our two children, Emily and Tom, in equal shares.”

See how they match? They are two individual Wills, but their instructions are a mirror image. This is the most common arrangement for couples in the UK, whether they are married, in a civil partnership, or in a long-term relationship.

The core idea is simple: the first person to pass away leaves their entire estate (their property, money, and possessions) to the surviving partner. Then, when the second partner eventually passes away, the combined estate is passed on to the next generation or other chosen beneficiaries.

Are Mirror Wills the Same as Joint Wills?

This is a common point of confusion, so let’s clear it up. No, they are not the same.

Mirror Wills are two separate Wills. This is crucial because it means either person can change or cancel their Will at any time without needing the other’s permission (though it’s good manners to have a chat about it!).
A Joint Will is a single document signed by two people, which is meant to cover both of them. These are extremely rare in the UK today because they are very inflexible and can cause legal headaches. Solicitors almost always advise against them.

For all intents and purposes, when couples plan their Wills together, they are almost certainly talking about making Mirror Wills.

Who Are Mirror Wills For?

Mirror Wills are most popular with couples who have similar wishes and trust each other completely. This typically includes:

Married Couples: The most common users of Mirror Wills.
Civil Partners: The legal framework is very similar to marriage, making Mirror Wills a logical choice.
Unmarried Couples: Long-term partners who live together and share their lives often find Mirror Wills are a straightforward way to ensure the survivor is provided for.

Essentially, if you and your partner think, “Whatever I have should go to you, and then to the kids,” then you’re thinking along the lines of a Mirror Will.

The Inner Workings: What Goes Into a Mirror Will?

While the main “leave it all to each other, then the kids” instruction is the heart of a Mirror Will, there are other important jobs a Will has to do. Your Mirror Wills will also need to name:

1. Executors

An Executor is the person (or people) you trust to carry out your Will’s instructions. They are responsible for gathering your assets, paying any debts or taxes, and making sure your beneficiaries get what you intended.

In Mirror Wills, it’s common for a couple to appoint each other as the Executor for the first death. But you also need to name replacement or “substitute” Executors to take over after the second partner dies. These are often adult children, other trusted family members, or a professional like a solicitor. You can have up to four.

2. Guardians for Children

If you have children under 18, this is arguably the most important part of your Will. You can appoint Guardians to look after your children if both parents pass away. Without this appointment, a court will have to decide who cares for your children, which can be a stressful and uncertain process for everyone involved.

In your Mirror Wills, you and your partner would appoint the same people as Guardians.

3. Specific Gifts (Legacies)

You might want to leave a specific item or a set amount of money to someone. This is called a legacy. For example:

“I leave my collection of vintage vinyl records to my nephew, James.”
“I give £1,000 to Cancer Research UK.”

In Mirror Wills, these gifts are often set to only be given after the second partner dies, to ensure the survivor has full access to all the assets during their lifetime.

4. The Residuary Estate

This is the legal term for “everything else” that’s left over after any debts, funeral expenses, and specific gifts have been paid. In a standard Mirror Will, the residuary estate is left to the surviving partner on the first death, and then to the children (or other beneficiaries) on the second death.

The Big ‘What Ifs’: Navigating Life’s Changes

Mirror Wills work perfectly in a simple, linear world where life goes exactly to plan. But life isn’t always like that. This is where the flexibility of Mirror Wills can become their biggest weakness.

Let’s explore some common scenarios.

What Happens When the First Partner Dies?

When the first partner passes away, their Will comes into effect. The surviving partner, usually acting as the Executor, will go through a process called Probate. This is the legal procedure for getting the authority to deal with the deceased’s estate.

Once Probate is granted, all the assets from the deceased partner are transferred into the survivor’s name. From that point on, the surviving partner owns everything. The Will of the person who died has now done its job and is finished.

This is the most critical point to understand about Mirror Wills. The survivor now has complete freedom. They can write a new Will and leave the combined estate to whomever they choose. They are not legally bound by the wishes expressed in the original Mirror Will.

The Big Risk: What if the Survivor Changes Their Mind?

David and Sarah make Mirror Wills, leaving everything to each other and then to their children, Emily and Tom.

David passes away first. Sarah inherits everything. A few years later, Sarah falls out with Tom. She decides to write a new Will, leaving everything she owns—including all the assets she inherited from David—solely to Emily.

Is this allowed? Yes, absolutely.

Because Mirror Wills are separate documents, the survivor can revoke their Will and create a new one at any time. There is no legal obligation for Sarah to stick to the original plan. Tom is completely disinherited, and there’s nothing he can do about it. This is the fundamental risk of Mirror Wills: they are based on trust, not on a legally binding agreement.

A Note on Mutual Wills

This is where the distinction with another type of Will becomes important. Mutual Wills are Wills where two people agree not to change them without the other’s consent. After the first person dies, the survivor is legally bound by the terms and cannot change their Will.

Mutual Wills sound like a good solution, but they are incredibly rigid and can cause huge problems if the survivor’s circumstances change (e.g., they need money for care costs). For this reason, solicitors rarely recommend them. Mirror Wills, based on trust, remain the standard for most couples.

What if We Get Divorced?

If you get divorced or your civil partnership is dissolved, the law in England and Wales has a clever safeguard. Under the Wills Act 1837, any parts of your Will that appoint your ex-spouse as Executor or leave them any assets are automatically cancelled upon the finalisation of your divorce (the decree absolute). The rest of the Will remains valid.

For example, if your Will left everything to your spouse and then to your children, a divorce would effectively cut out your ex-spouse, and your estate would go directly to your children.

However, it’s always best practice to write a completely new Will after a major life event like divorce to ensure your wishes are clear and up-to-date.

The Remarriage Trap: Sideways Disinheritance

This is one of the most significant risks associated with Mirror Wills, especially in blended families.

Let’s go back to David and Sarah.

David dies. Sarah inherits the family home, savings, everything.
A few years later, Sarah meets and marries a new partner, Peter.
Under English law, marriage automatically revokes any existing Will. So, the Mirror Will Sarah made with David is now invalid.
If Sarah dies without making a new Will, the Rules of Intestacy apply. Under these rules, her new husband, Peter, would inherit a large portion (if not all) of her estate. The children, Emily and Tom, could get nothing.

This is known as “sideways disinheritance.” The family wealth has gone sideways to a new spouse, completely bypassing the children from the first relationship. Even if Sarah did make a new Will with Peter, she might choose to leave everything to him, trusting him to provide for Emily and Tom later—which puts them back at square one, relying on someone else’s goodwill.

Protecting Your Children: How to Add Security to Your Will

If the risks of disinheritance worry you, the good news is that you can build protections into your Wills. This is often done by using Trusts.

A Trust is essentially a legal arrangement where you give assets to people you trust (the Trustees) to look after for the benefit of others (the Beneficiaries).

The Life Interest Trust: A Popular Solution

A common way to protect your children’s inheritance is to include a Property Protection Trust or Life Interest Trust in your Wills.

Here’s how it works, often in relation to the family home:

David and Sarah change their property ownership from “Joint Tenants” to “Tenants in Common.” This means they each own a distinct 50% share of the house, which they can leave to whomever they want in their Will. (As Joint Tenants, the house automatically passes to the survivor, regardless of what a Will says).
In his new Will, David leaves his 50% share of the house in a Trust.
The terms of the Trust say: “Sarah has the right to live in the property for the rest of her life. She is the Life Tenant. But when she passes away, my 50% share of the house must go to our children, Emily and Tom.”

What does this achieve?

Security for the Survivor: Sarah can’t be kicked out of her home. She is secure for life.
Protection for the Children: Sarah can’t leave David’s 50% share to a new partner or anyone else. It is legally ring-fenced for the children.
Care Fees Protection: If Sarah later needs to go into residential care, the local authority can only assess her on her own assets. David’s 50% share, held in the Trust, cannot be touched to pay for her care fees.

This type of planning is a little more complex than a basic Mirror Will, but it provides powerful protection against sideways disinheritance and can help preserve family assets.

Practical Steps and Costs

How Do I Make Mirror Wills?

You have a few options:

Use a Solicitor: This is the gold standard. A qualified solicitor will discuss your circumstances, advise you on potential risks (like sideways disinheritance), and ensure the Wills are drafted and signed correctly. They will also store the Wills for you.
Use a Professional Will Writer: There are many professional Will writers who are not solicitors. Some are excellent and belong to professional bodies like the Society of Will Writers. Ensure you check their credentials and insurance.
DIY Will Kits: You can buy Will-writing kits from stationers or online. This is generally not recommended. It is incredibly easy to make a mistake when drafting or signing (witnessing) a Will, which could make it invalid. The money you save now could cost your family thousands in legal fees later.

How Much Do They Cost?

Prices vary, but here’s a rough guide for 2025 in the UK:

Solicitor-drafted Mirror Wills: Expect to pay between £300 and £600 + VAT for a straightforward pair of Mirror Wills.
Mirror Wills with Trusts: If you include protective trusts, the cost will be higher, typically in the range of £600 to £1,000 + VAT.
Will Writers: Prices are often a little lower than solicitors’.
DIY Kits: Around £20-£30, but as mentioned, this carries significant risk.

Think of the cost as an investment in peace of mind for your family.

Related Legal Essentials: LPAs and Inheritance Tax

When making a Will, it’s a good idea to think about two other key areas of estate planning.

Lasting Power of Attorney (LPA)

A Will deals with what happens after you die. A Lasting Power of Attorney (LPA) deals with what happens if you lose the mental capacity to make decisions for yourself while you are still alive (for example, due to dementia or a stroke).

There are two types:

Health and Welfare: Allows your chosen attorneys to make decisions about your medical care and daily life.
Property and Financial Affairs: Allows your attorneys to manage your bank accounts, pay bills, and sell your property.

It makes sense for a couple to set up LPAs at the same time as their Mirror Wills, appointing each other as their attorney.

Inheritance Tax (IHT)

Inheritance Tax (IHT) is a tax on the estate of someone who has died. The good news is that most people in the UK don’t have to pay it.

Here are the key points for couples:

Spouse Exemption: Anything you leave to your spouse or civil partner is completely free from IHT, no matter how large your estate is.
Nil-Rate Band: Every individual has a tax-free allowance, called the Nil-Rate Band (NRB), which is currently £325,000.
Transferable Nil-Rate Band: When the first spouse dies and leaves everything to the survivor, they don’t use their NRB (because of the spouse exemption). This unused allowance can be transferred to the survivor. This means the surviving partner can have a total tax-free allowance of up to £650,000 (£325,000 x 2).
Residence Nil-Rate Band (RNRB): There is an additional allowance if you leave your main home to your direct descendants (children or grandchildren). This is currently £175,000 per person, which is also transferable between spouses.

This means a couple could potentially pass on up to £1 million completely tax-free (£325k + £175k = £500k, x 2 = £1m).

For most couples, standard Mirror Wills are perfectly efficient for IHT purposes. The structure ensures the transferable allowances can be used to their full potential.

So, Are Mirror Wills Right for You?

Mirror Wills are a simple, cost-effective, and perfectly suitable solution for many couples. But they are not a one-size-fits-all answer.

Mirror Wills are likely a good choice if:

You are in a long-term, stable relationship.
You have the same wishes for your estate.
You trust your partner implicitly to do the right thing if you die first.
Your financial affairs are relatively straightforward.

You should think carefully and seek professional advice if:

You have children from a previous relationship (i.e., you are a blended family). The risk of “sideways disinheritance” is much higher.
You are concerned that your partner might remarry and divert assets away from your children.
You own property or business assets and want to protect them for future generations.
Your estate is large and might be subject to Inheritance Tax.

Making a Will is a profound act of care for the people you love. It removes uncertainty and ensures they are looked after when you’re no longer there to do it yourself. Whether simple Mirror Wills or a more complex arrangement involving trusts is right for you, the most important step is to take action. Don’t put it off. Have the conversation, get the advice, and put a proper plan in place. Your family will thank you for it.