According to research from the Money and Pensions Service, 56% of UK adults still don’t have a will at all. If you’re a couple in Swindon sorting this out, mirror wills are probably the first option you’ll hear about. They’re the most popular choice for couples in the UK — straightforward, well-priced, and for most people exactly the right call.
But there’s a risk that doesn’t come up enough in conversations about mirror wills. I want to make sure you understand it before you decide.
What Are Mirror Wills?
Mirror wills are two separate wills — one for each partner — that reflect each other’s wishes. Typically, each document says the same thing in reverse: everything goes to the surviving partner first, then on to named beneficiaries (usually children) when the second partner dies.
They’re called mirror wills because the content mirrors, not because they’re a single joint document. Each will is legally independent — a fact that matters more than it might seem.
How Do Mirror Wills Work in Practice?
The basic structure is simple: Partner A leaves everything to Partner B. Partner B leaves everything to Partner A. Both documents then name the same final beneficiaries — usually children or grandchildren — to inherit after both partners have gone.
When the first partner dies, their will goes through probate. The surviving partner inherits, usually outright. The surviving partner’s own will remains in place, unchanged by the first death, and takes effect in the normal way when they die.
Here’s something that often surprises people: the two wills are entirely independent documents. Unlike a mutual will (a rarer, more legally complex arrangement), either partner can change their will at any time — including after the first death. That flexibility is generally a benefit. But it also creates a specific risk, which I’ll come to shortly.
The Benefits of Mirror Wills for Couples
There are good reasons mirror wills are the default choice for couples in the UK:
- Simplicity. One process, two documents. You talk through your wishes together and sign simultaneously — it’s efficient and clear.
- Cost. Having your wills drawn up together is cheaper than each coming to us separately. At Riverwise, mirror wills for a couple are £350 for the pair, compared to £200 each if you came to us independently.
- Alignment. You get to confirm, together, that you’ve made the same decisions — who’s your executor, what happens to the house, who looks after the children. Nothing assumed, everything agreed.
- Speed. Because the wishes mirror each other, the drafting is quicker — which means less back and forth before your wills are signed and in place.
The Risk You Need to Know About: Sideways Disinheritance
This is the part I want you to hear clearly.
Because each will is independent, the surviving partner can change theirs after the first death. A standard mirror will contains nothing to prevent this. In most cases, that’s fine — life changes, and flexibility is genuinely valuable.
But it creates a risk called sideways disinheritance. Here’s how it plays out: the first partner dies, everything passes to the survivor. The survivor later remarries. In the UK, a new marriage automatically revokes an existing will. The survivor’s new partner may inherit everything. The children from the original relationship — the people both partners intended to provide for — receive nothing.
This isn’t anyone doing something deliberately wrong. It’s a structural gap in how mirror wills work. And it’s more common than most people expect.
What Happens to the Surviving Partner’s Will After the First Death?
Nothing, automatically. The surviving partner’s will stays exactly as it was when they signed it. They can leave it untouched, or they can change it — and they have every legal right to do so.
There’s no mechanism in a standard mirror will that locks the survivor’s document into its original form.
If protecting your children’s inheritance matters to you, the most common solution is to add a Protective Property Trust to your mirror wills. When the first partner dies, the family home passes into a trust rather than outright to the survivor. The survivor can continue living there — their daily life is unaffected — but the capital interest in the property is ringfenced for the children.
Mirror Wills vs. Separate Wills — Which Is Right for You?
Not every couple’s situation calls for the same solution. Here’s a summary of the main options:
| Mirror Wills | Separate Wills | Mirror Wills + Protective Property Trust | |
|---|---|---|---|
| Cost (Riverwise) | £350 pair | £400 pair (£200 each) | £575 pair |
| Best for | Couples with aligned wishes, no complex estate | Significantly different wishes or complex estates | Couples wanting to ringfence the family home for children |
| Protects against sideways disinheritance? | No | No | Yes (for the property) |
| Can be changed later? | Yes | Yes | Yes, but the trust terms are fixed |
| Complexity | Low | Low–Medium | Medium |
For most couples — married, with children from the same relationship, no complex estate issues — mirror wills are the right choice. If protecting the family home for your children is a priority, the trust option is worth the extra cost.
How Much Do Mirror Wills Cost in Swindon?
At Riverwise Estate Planning, mirror wills for a couple cost £350. If you add a Protective Property Trust to address sideways disinheritance, the cost is £575 for the pair.
We start with a free initial consultation — no obligation, no pressure. We’ll talk through your situation, explain your options in plain English, and help you decide what’s right for you before anything is signed.
If you’d prefer to meet at home rather than coming into our Swindon office, we offer home visits across the area at no extra charge.
It’s also worth thinking about your Lasting Power of Attorney at the same time — most couples find it easier to tackle both in one conversation. Get in touch and we’ll find a time that works for you.
A word from Woody — our Chief Happiness Officer (he is a dog): Woody has strong views on inheritance, specifically that treats should be distributed equally and that sideways disinheritance by a new pet is not acceptable. He has also asked me to confirm that a Protective Property Trust cannot be used to ringfence the biscuit tin. It cannot. He remains disappointed.
Frequently Asked Questions — Mirror Wills in Swindon
Are mirror wills legally binding in the UK?
Yes. Mirror wills are two standard, independently valid wills — each signed, witnessed and dated in the same way as any single will. They’re the most common arrangement for couples in the UK.
Can we change our mirror wills after they’ve been signed?
Yes — either partner can change their will at any point, independently of the other. There’s no requirement to notify your partner or keep the wills in their original form. This flexibility is one of the reasons most couples prefer mirror wills over mutual wills.
What’s the difference between mirror wills and mutual wills?
Mirror wills reflect each other but remain independent documents — either partner can change theirs at any time. Mutual wills include a contractual agreement not to change them after the first death. Mutual wills are legally complex, can be difficult to enforce, and are rarely recommended. For most couples, mirror wills (with a Protective Property Trust if needed) are a better approach.
Do unmarried couples need wills?
Yes — especially so. UK intestacy rules don’t recognise unmarried partners, which means without a will, a cohabiting partner could receive nothing from your estate regardless of how long you’ve been together. If you’re not married or in a civil partnership, sorting your wills is essential, not optional. Read more about when to review your will.
Can we get our mirror wills sorted at home?
Yes. Riverwise offers home visits across Swindon and wider Wiltshire — including Chippenham, Marlborough and Royal Wootton Bassett — at no extra cost. Contact us and we’ll find a time that works for you.
