Bigamy Explained: What It Means and What Happens Next

By Garry SteedmanPublished 17 September 2026Last reviewed 17 September 202611 mins read9 sections

Part of: Divorce Specialists

Bigamy is the offence of marrying one person while you are still lawfully married to another. In England and Wales it is a crime under section 57 of the Offences against the Person Act 1861. The later marriage is also void, so the law treats it as one that never took effect (Matrimonial Causes Act 1973, section 11(b)). If you have just found out, our divorce specialists can talk you through both sides.

This guide covers England and Wales only. It explains what the word means, what the criminal law says, and where a void marriage leaves your home, your money and your children. If you have just found a second marriage certificate, or a letter that does not add up, it is normal to feel shaken. You do not have to work everything out today.

Reviewed by: Iblal Iqbal, Partner & Family Law Strategist, Kabir Family Law

What is bigamy? Meaning and legal definition

Bigamy definition: going through a marriage ceremony while an earlier marriage is still legally in force. The earlier marriage stays in force until a court ends it, or until one spouse dies. So a long separation, however final it feels, does not free anyone to marry again.

A bigamist is the person who goes through that second ceremony. The other party often knows nothing about it. Some people only find out years later, when a pension claim, a mortgage application or a death certificate stops adding up.

One thing catches many people out: a divorce is not over when the papers go in. It ends only when the court makes the final order, so our guide to the decree absolute and the final order is worth a read if you are unsure.

Is bigamy a crime in the UK?

Yes. Section 57 makes it an offence to marry again during the life of a former husband or wife. It applies in Northern Ireland as well as in England and Wales. Scotland has its own rules, and there the offence is a crime under Scots common law (Scottish Government FOI release).

What is the maximum sentence for bigamy?

The maximum sentence is seven years in prison. The charge is triable either way, so a magistrates’ court or the Crown Court can hear it (Magistrates’ Courts Act 1980, Schedule 1). Section 57 still states the seven-year limit in its old wording of “penal servitude”. The Criminal Justice Act 1948 turned that into ordinary imprisonment for the same maximum term. A magistrates’ court has lower sentencing powers, so the longest sentences can only come from the Crown Court.

When is it not an offence?

Section 57 sets out exceptions. The most familiar is the seven-year rule. It applies where a husband or wife has been continually absent for the seven years before the ceremony, and the other person did not know they were alive during that time. The other exceptions cover someone who was already divorced, and someone whose earlier marriage a court had declared void. A last one covers a second marriage abroad by someone who was not, in the Act’s old words, “a subject of Her Majesty”.

However, the seven-year rule is only a defence to a bigamy charge. If the missing spouse is in fact alive, the later marriage is still void. The safer route is a court declaration of presumed death. Once final, it ends the earlier marriage for all purposes (Presumption of Death Act 2013, s.3).

Finally, the criminal side and the family side are separate. Many families meet the problem the other way round: the marriage they thought they had turns out not to exist. You can sort out the family side without waiting for the police.

What is the difference between bigamy and polygamy?

The two words describe different things. One names a criminal offence here. The other describes a marriage form that some countries allow. They overlap, but they are not interchangeable, and the family court treats them differently.

Is the second marriage valid?

No. The later marriage is void from the moment of the ceremony, because one party was already lawfully married (Matrimonial Causes Act 1973, s.11(b)). Nothing you do afterwards makes it valid.

Void and voidable are not the same. A void marriage never had legal effect. A voidable marriage counts until a court ends it, for example where it was never consummated or one person did not truly consent (GOV.UK: how to annul a marriage).

That difference changes what you apply for. You do not divorce a void marriage; you ask the court for a nullity order instead. Unlike divorce, you can apply in the first year of the marriage. The court fee is £612, and you may get help with it on a low income (GOV.UK: apply for an annulment). Our guide to marriage annulment walks through the stages, from the application to the conditional order and then the final order.

Strictly, the law already treats a void marriage as one that never existed. Even so, most people want the order. It gives you a document to show a bank, a pension provider or a registrar if you marry again. It also opens the door to financial orders, which matter far more than the label does.

What happens to your home, money and children after bigamy?

A void marriage does not leave you without a claim. When the court makes a nullity order, it can make the same kinds of orders as on divorce. These include maintenance, a lump sum, orders about property and pension sharing (Matrimonial Causes Act 1973, s.23, s.24 and s.24B). The court then weighs the usual factors, such as each person’s needs and contributions (s.25). That puts you in a stronger position than an unmarried couple, as our guide to common law marriage explains.

If the other person dies and you married in good faith, you can still count as their spouse when claiming against their estate. That changes if, during their lifetime, a court ended the marriage or you married someone else (Inheritance (Provision for Family and Dependants) Act 1975, s.25(4)).

What about the children?

Children have protection in their own right. The law treats a child of a void marriage as legitimate if either parent reasonably believed the marriage was valid at conception, or at the ceremony if that came later. For children born after the relevant part of the Family Law Reform Act 1987 took effect, the law presumes that belief unless someone shows otherwise. The rule applies where the father had his domicile in England and Wales at the birth (Legitimacy Act 1976, s.1). In that case the father also has parental responsibility, just as a married father would (Children Act 1989, s.2). Both parents must still maintain their children (Child Support Act 1991, s.1).

What should you do if you have just found out?

Take it in order. The first few steps are about evidence, not confrontation, and they are easier to do before anyone knows you are asking.

1. Save what you already have. Keep the marriage certificate, messages, photographs and anything that fixes a date. Copies are enough, so take them now rather than later.
2. Order the certificates. You can order a copy of a marriage certificate from the General Register Office through GOV.UK. Two certificates side by side usually answer the question.
3. Check the earlier marriage really ended. Ask to see the final order, or the decree absolute if the divorce was older. If nobody can produce it, GOV.UK explains how to get a copy. A separation agreement, a religious divorce or a long silence is not proof.
4. Get advice before you apply. Nullity, divorce and a financial claim are three different applications. Starting the wrong one can cost you time and fees, so it helps to speak to a specialist first.
5. Deal with money early. Find out what is in joint names, what a pension says and who is on the mortgage. These answers shape what the court can do later.
6. Treat the police question separately. Reporting is your choice. There is no rule that it must come first, and you can start the family side without it.

Frequently asked questions

What is a bigamist?

A bigamist is a person who marries again while an earlier marriage is still legally in force. The word names the person; the offence has its own name. Someone can become one without meaning to, for example where they believed a divorce had gone through and it had not.

Why was bigamy made illegal?

Marriage decides who shares property, who inherits and who counts as family, so the law needs one clear answer to who is married to whom. The offence is older than the 1861 Act. That Act consolidated and amended earlier criminal law, and section 57 is the version still in force today.

Is bigamy a crime outside England and Wales?

Yes, in many places. Section 57 also applies in Northern Ireland, and Scotland treats it as a crime under its own common law. In Canada, section 290 of the Criminal Code defines the offence. If a ceremony took place abroad, you will usually need advice on that country’s law as well as ours.

What if one of you was in a civil partnership?

The result is much the same. A marriage is void if either person was already a civil partner (Matrimonial Causes Act 1973, s.11(b)). A civil partnership is also void if either person was already married or a civil partner when they registered it (Civil Partnership Act 2004, s.49, with s.3). Section 57 itself speaks only of marrying while married. However, knowingly making a false declaration to register a civil partnership is a separate offence (s.80).

Does a void marriage mean I get nothing?

No. When the court makes a nullity order, it can make the same kinds of financial orders as on divorce, including orders about a home, a pension, maintenance or a lump sum. What you receive depends on your circumstances, such as your needs and contributions, not on the label attached to the marriage.

Do I still need a divorce if my marriage was void?

No, because you cannot divorce a marriage that never existed in law. You apply for a nullity order instead. If your own earlier marriage is still valid, though, that one may well need ending properly, and our guide to no-fault divorce explains how that now works.

Just found out your marriage may not be valid? Get advice before your first application

Finding out is a shock, and it is natural to want to do something straight away. The first application sets the direction, though, and nullity, divorce and a financial claim are not the same thing. Starting with the wrong one can cost you time and money. Book a free initial consultation, where one of our specialists gives you initial advice tailored to your circumstances. You can also read how our divorce specialists assist and advise.

Expert Tip

We are commonly asked whether to go to the police before doing anything else. There is no rule that says you must report it before you apply to the family court. What does cause delay is missing paperwork. Before you apply, get copies of both marriage certificates and, if one exists, the final order that ended the earlier marriage. The court will need to see that the earlier marriage was still in force on the day of the later ceremony.

Garry Steedman, Family Law Consultant (Divorce, Children & TOLATA)