The short answer
- A diagnosis does not stop a marriageThe law presumes a person can make their own decisions. What counts is whether they understand marriage at the time, not the name of their condition.
- The test for marriage is a low oneThey need to understand that it is a marriage and the duties that come with it. Whether this marriage is a wise one is not part of the test.
- Nobody can say yes for themAn attorney, a deputy, a relative or a court cannot consent to a marriage on someone else's behalf. The decision is theirs or it cannot be made.
- A registrar can stop the marriageA doubt about capacity can come up when notice is given or at the ceremony, and a marriage cannot go ahead if a person lacks capacity.
- Marriage cancels an existing willIn England, Wales and Northern Ireland it does, and a new will needs a harder test. This rule still applied in October 2026.
Based on the Mental Capacity Act 2005, the Wills Act 1837, case law and General Register Office guidance. It explains the law in general and is not legal advice about a particular marriage. October 2026.
This guide is part of the wedding carers section, which helps families plan a wedding around an older or frail relative. It deals with a different question from the rest: whether a person with dementia can be the one getting married.
What the law asks
A dementia diagnosis does not stop someone marrying
The law in England and Wales starts from the position that every adult can make their own decisions, and it judges capacity one decision at a time. The question is never whether somebody has dementia. It is whether they can make this particular decision, at the time it has to be made.
The Mental Capacity Act 2005 sets out the starting point in section 1. A person must be assumed to have capacity unless it is shown that they do not. They must not be treated as unable to decide until everything practical has been done to help them. Making a choice other people think unwise is not, on its own, a sign that they lack capacity. Section 2 adds that a lack of capacity cannot be established just by pointing to someone's age or to a condition such as dementia.
For marriage, the test comes from the courts. In Sheffield City Council v E, decided in 2004, the judge said a person must understand more than the fact that they are taking part in a ceremony. They must understand the nature of the marriage contract and the duties and responsibilities that normally come with being married. He also said the contract of marriage is "in essence a simple one, which does not require a high degree of intelligence to comprehend". The court is not asking whether this marriage is sensible, which is a separate question from capacity.
Four decisions, four separate tests
Getting married
A low bar, set deliberatelyWhat the person needs to understand
Understanding that this is a marriage ceremony and what the words mean, and the duties and responsibilities that normally come with being married. It does not ask whether marrying this particular person is wise.
If they cannot decide
Nobody. No attorney, deputy, relative or court can consent to a marriage for someone else.
Sheffield City Council v E (2004); Mental Capacity Act 2005, section 27
Making or changing a will
Asks moreWhat the person needs to understand
Understanding what a will does, having a broad idea of what they own, and being able to think about the people who might expect to inherit. When someone has dementia, a solicitor may ask a doctor to confirm this before the will is signed.
If they cannot decide
The Court of Protection can be asked to make a statutory will on their behalf.
Banks v Goodfellow (1870); Mental Capacity Act 2005, section 18
Managing money and property
Depends on the decisionWhat the person needs to understand
Understanding the information about the decision in front of them, holding on to it long enough, weighing it up, and telling someone what they have chosen.
If they cannot decide
An attorney under a lasting power of attorney for property and financial affairs, or a deputy appointed by the Court of Protection.
Mental Capacity Act 2005, section 3
Where they live and the care they have
Depends on the decisionWhat the person needs to understand
The same four-part test, applied to the particular choice being made at the time.
If they cannot decide
An attorney for health and welfare, or the people involved acting in their best interests.
Mental Capacity Act 2005, sections 3 and 4
Why the difference matters in England, Wales and Northern Ireland
The wedding
Getting married cancels any will they made before, unless it was written with this marriage in mind.
Afterwards
A new will needs the will-making test, which asks more than the marriage test does.
If they cannot meet it
The intestacy rules decide who inherits, with the husband or wife first, unless the Court of Protection makes a statutory will.
So somebody whose attorney now manages their bank account may still understand what marrying means. Capacity can also come and go. Some people with dementia are clearer at some times of day than others, and for some the late afternoon is harder, which is the pattern described in what is sundowning?. What matters is how they are at the moments the registrar looks at, covered below. Our guide to mental capacity and how it is assessed explains the general four-part test in more depth, and dementia care is the wider guide to the condition.
Nobody can decide for them
No attorney, relative or court can consent to a marriage for someone else
A lasting power of attorney lets someone make decisions for a person who can no longer make them. Marriage is one of the decisions the law keeps out of that arrangement altogether.
Section 27 of the Mental Capacity Act lists a small group of decisions that nothing in the Act allows anyone to make on another person's behalf. Consenting to marriage or civil partnership is the first on the list. So there is no route by which a family, an attorney or a judge can say yes to a marriage for somebody who cannot say yes themselves. The same section also means an attorney cannot say no to a marriage on the person's behalf. If the person has capacity to marry, the choice is theirs, even if their attorney or their children disagree with it.
| What they can do | What they cannot do | |
|---|---|---|
| The person themselves | Decide to marry, if they understand what marriage is when they give notice and when they marry | Marry at a time when they do not understand it, even if they wanted to before |
| An attorney under a lasting power of attorney | Carry on managing money, property or welfare decisions within the power, after the wedding as before | Consent to the marriage, or refuse it, on the person's behalf |
| A deputy appointed by the Court of Protection | Make the decisions the court has given them power over, such as finances | Consent to or refuse a marriage for the person |
| The Court of Protection | Declare whether the person has or lacks the capacity to marry, if someone applies to it | Give consent to a marriage on the person's behalf |
| The registrar | Ask questions at notice and at the ceremony, and stop a marriage going ahead if a person lacks capacity | Refuse a marriage because they think it unwise, if both people have capacity |
| Children and other family | Raise a concern with the registrar, enter a formal objection called a caveat, or ask for a safeguarding enquiry | Stop a marriage because they disapprove of it, or agree to it in the person's place |
The person themselves
- What they can do
- Decide to marry, if they understand what marriage is when they give notice and when they marry
- What they cannot do
- Marry at a time when they do not understand it, even if they wanted to before
An attorney under a lasting power of attorney
- What they can do
- Carry on managing money, property or welfare decisions within the power, after the wedding as before
- What they cannot do
- Consent to the marriage, or refuse it, on the person's behalf
A deputy appointed by the Court of Protection
- What they can do
- Make the decisions the court has given them power over, such as finances
- What they cannot do
- Consent to or refuse a marriage for the person
The Court of Protection
- What they can do
- Declare whether the person has or lacks the capacity to marry, if someone applies to it
- What they cannot do
- Give consent to a marriage on the person's behalf
The registrar
- What they can do
- Ask questions at notice and at the ceremony, and stop a marriage going ahead if a person lacks capacity
- What they cannot do
- Refuse a marriage because they think it unwise, if both people have capacity
Children and other family
- What they can do
- Raise a concern with the registrar, enter a formal objection called a caveat, or ask for a safeguarding enquiry
- What they cannot do
- Stop a marriage because they disapprove of it, or agree to it in the person's place
Mental Capacity Act 2005, sections 15 and 27; Marriage Act 1949, section 29; General Register Office mental capacity guidance.
There is one more piece of law that protects a person who cannot consent. Under section 121 of the Anti-social Behaviour, Crime and Policing Act 2014, it is a criminal offence in England and Wales to arrange a marriage for someone who lacks the capacity to consent to it, whether or not anyone pressured them. The government's Forced Marriage Unit gives advice on this, and its page says plainly that arranging a marriage for somebody who lacks capacity counts as forced marriage.
If you are an attorney for a parent who wants to marry, your role carries on as before. Lasting power of attorney and dementia explains what an attorney can and cannot do.
What the registrar does
What happens at the register office if they are unsure about capacity
Every civil marriage in England and Wales starts with each person giving notice at a register office, at least 29 days before the ceremony. A doubt about capacity can come up at that point or on the day itself.
- 1
Giving notice
At least 29 days beforeEach of the couple visits the register office for the district where they have lived for the past seven days. The registrar asks each of them questions and records the notice, so this is the first point at which a doubt about capacity can come up. - 2
If the registrar has doubts
Before anything is bookedGeneral Register Office guidance suggests talking to the person privately, without family in the room, and discussing any concern with the superintendent registrar or the General Register Office straight away. - 3
The waiting period
The 28 days that followThe notice is displayed publicly. Anyone with a concern can enter a caveat, a formal objection, with the superintendent registrar. Nothing more is issued until the caveat has been looked into or withdrawn. - 4
The ceremony
On the dayThe person conducting the ceremony checks again that both people understand they are getting married and are doing so freely. A marriage cannot go ahead if one of them lacks the capacity to marry at that moment.
The General Register Office guidance for authorised persons, who conduct marriages in registered religious buildings, uses the same test as the courts. It reminds them that capacity must be presumed unless it is shown to be missing, and that a learning disability on its own should never be taken to mean a person cannot marry.
For the couple, a calm, well-timed visit helps. Give notice at the time of day the person is usually at their best, and let them answer the registrar's questions in their own words. If anything would help, such as a quieter room or more time, tell the register office when you book the appointment. The government's page on giving notice explains the documents to bring.
If the person cannot get to the register office because they are housebound or in hospital, there are different arrangements, including a faster route when someone is seriously ill. Getting married quickly in a hospital, hospice or at home covers each of them. The capacity question is the same whichever route is used.
Marriage and a will
Getting married cancels an existing will in England, Wales and Northern Ireland
Of all the legal effects of a marriage, this one can make the biggest difference to money, and it is one reason the law on wills has been under review.
Under section 18 of the Wills Act 1837, a will is revoked when the person who made it marries. The exception is a will that shows the person expected to marry a particular person and intended the will to survive that marriage. Northern Ireland has the same rule. In Scotland, marriage does not cancel a will, although a husband or wife there has legal rights to part of the estate whatever the will says.
The difficulty for someone with dementia is the difference between the two tests in the figure above. A person can meet the low test for marriage and no longer meet the higher test for making a will. If that happens, their old will is cancelled on the wedding day and they may not be able to make a new one. Their estate would then pass under the intestacy rules, which put a husband or wife first. The Court of Protection can be asked to make a statutory will for somebody who cannot make one, but that is a court application with its own forms and fees.
- 1837
Marriage revokes a will
The Wills Act sets the rule. The current wording of section 18 dates from 1982.
- 2025
The Law Commission recommends abolishing it
Its report Modernising Wills Law, published on 16 May 2025, says marriage should no longer revoke a will, partly because the rule can be exploited through predatory marriage.
- 2026
Waiting for the government
A full government response was expected within a year of the report. By October 2026 no response or bill had been published, and section 18 has no change recorded against it.
- Now
The old rule still applies
Until Parliament changes the law, a marriage in England or Wales still cancels an earlier will.
The Law Commission's final report describes a "predatory marriage" as one where someone marries a vulnerable person, sometimes a person who lacks capacity, to gain from their estate. Ending the revocation rule would remove one of the ways that can happen, but it has not been put into law, so families should plan on the basis of the law as it stands.
If your parent is marrying and has a will, the practical step is to see a solicitor before the wedding. A will can be written in contemplation of a named marriage, so that it survives it, provided the person still has the capacity to make a will. Will writing and protecting assets explains how to find help with a will.
If the family is worried
When the family has doubts, and what each route can do
Families come to this question from very different places. Some are delighted that a parent has found companionship late in life. Some are worried the person does not understand what they are agreeing to, or that someone is taking advantage of them. Both are reasonable, and the routes below are for a real concern about capacity or pressure.
Start by talking to the person, at a calm time and on their own if you can. Ask what the marriage means to them and what they think will change, and listen for whether they understand it rather than whether you agree with it. Disapproval of the match is not a legal reason to stop it, and pressing hard can damage your relationship with your parent at a time when they need you.
If your concern is about capacity or pressure, these are the people who can act on it.
The register office
Before or after notice is given
Adult social care
If you think they are at risk
A solicitor
For the will and the money
The GP or memory service
For a view on capacity
The Forced Marriage Unit
If they cannot consent
The Court of Protection
If the question needs a ruling
The guide to safeguarding adults and how to report explains what happens after a referral. If a marriage has already taken place and you believe the person did not understand it, the law does allow a marriage to be annulled where one of the couple did not validly consent, including because of unsoundness of mind, under section 12 of the Matrimonial Causes Act 1973. An application normally has to be made within three years of the wedding. It is a slow and uncertain route, and raising a concern before the wedding is far better.
If the wedding goes ahead
Planning the day around someone with dementia who is getting married
If both people have capacity and the wedding is going ahead, the rest is about making the day manageable for the person with dementia. Being the bride or groom means being at the centre of attention all day, which asks more than being a guest.
Things to settle before the day
0 of 5 ticked
The ceremony
The rest of the day
That last point matters more when the person marrying is also looked after by their partner. On their own wedding day, the partner should be able to be a bride or groom rather than a carer. A grown-up child, a close friend or a wedding carer who stays with them all day can take on the practical side, so the couple can enjoy the ceremony together.
Taking someone with dementia to a wedding explains how to shape the hours around their energy, and the wedding day care plan template gives you a printable sheet for medicines, routines and contacts. The accessible wedding venue checklist helps when choosing where to hold it. If the family is still deciding whether a relative with dementia should be at a wedding as a guest, should someone with dementia come to the wedding? talks that decision through.
Questions
Questions families ask about dementia and marriage
Yes, if they have the capacity to marry at the time they give notice and at the ceremony. The law presumes that every adult has capacity, and a dementia diagnosis is not on its own a reason to say otherwise. The test is whether they understand that they are getting married and the duties and responsibilities that normally come with marriage. The courts have described it as a simple test that does not need a high degree of intelligence.
It is legal if they have capacity to consent to the marriage. It is not lawful if they lack that capacity, and in England and Wales it is a criminal offence to arrange a marriage for someone who lacks the capacity to consent to it, whether or not they were pressured. A registrar who doubts a person's capacity can stop the marriage going ahead.
Yes. Alzheimer's disease is the most common cause of dementia, and the same rules apply. What matters is whether the person understands what marriage is when they marry, not the type of dementia they have or how long ago they were diagnosed.
No. Section 27 of the Mental Capacity Act 2005 means no attorney, deputy or court can consent to a marriage on someone else's behalf, and an attorney cannot refuse one for them either. If you are worried the person lacks capacity, tell the register office, so the registrar knows before they assess it. A caveat, a safeguarding referral or an application to the Court of Protection for a declaration are the formal routes.
In England, Wales and Northern Ireland, yes, unless the will was made in contemplation of that particular marriage. The Law Commission recommended ending this rule in May 2025, but it had not been changed by October 2026. In Scotland, marriage does not cancel a will. A person with dementia may meet the test for marriage and not the harder test for making a new will, so the will should be looked at with a solicitor before the wedding.