Archive Website of the UK government

When a marriage is ‘void’

A marriage is not legal (and called a ‘void marriage’) if:

• either person in the marriage was under 16 years old at the time of the wedding
• the marriage is between two males or two females (this would be a civil partnership)
• either person was already married to or in a civil partnership with someone else at the time of the wedding (called ‘bigamy’)
• the marriage is between close relatives

Close relatives you can’t legally marry

Close relatives you can’t legally marry include your:

• mother or father - including adoptive or former adoptive mother or father
• daughter or son - including adoptive or former adoptive son or daughter
• brother, sister, half brother or half sister
• niece, nephew, aunt or uncle
• grandmother, grandfather, granddaughter or grandson

These are sometimes called ‘prohibited degrees of relationship’.

If you marry a close family member the marriage will be void, even if you’re not aware of your family relationship.

For example, if a brother and sister were adopted by different families soon after birth and meet later in life, they couldn’t legally marry. If they did marry, the marriage would be 'void' and not recognised by the law.

Step-parents and step-children can sometimes marry. But they must be at least 21 years old and have not lived in the same household before the step-child was 18 years old.

If you want advice on whether a potential marriage between family members would be legal, check with your local register office.

• Search for your local register office Opens new window

Marrying more than one wife

‘Polygamous’ marriage is where a husband has more than one wife.

You can’t enter into a legal polygamous marriage in the UK. Any marriage that takes place here when the husband is already married would be void.

If a marriage takes place overseas and the husband and wife are living in the UK, it would also be void if either one was already married to someone else.

A polygamous marriage can only be recognised in the UK if:

• the marriage took place in a country where it is allowed
• both the husband and wife were living abroad at the time of the wedding

If you think a marriage is ‘void’

If you think a marriage is ‘void’ because of any of the reasons above, technically you don’t have to do anything to legally end it. This is because the law says that it never existed.

But you may find it useful to get legal paperwork to prove that the marriage never existed.

For example, if you want to get married again you will need to be able to prove you are not already married.

You may be breaking the law if your marriage is void because you were already married to someone else (called ‘bigamy’).

If you apply to have your marriage annulled, you can also apply to the court to help you sort out your finances as if you had been married. You can do this by asking the court to make a ‘decree of nullity’. See ‘How to end a marriage that’s ‘void’ or ‘voidable’ for more information.

• How to annul a marriage that's 'void' or 'voidable'

When a marriage is ‘voidable'

There are specific reasons why a marriage can be declared ‘voidable’. This means that you can end the marriage by annulment instead of by divorce.

If you want to do this, you will have to ask the court to ‘annul’ it. This will mean that the marriage will never have existed in the eyes of the law.

But until the court annuls a ‘voidable’ marriage, you will still be married.

A marriage can be ‘voidable’ if:

• it hasn’t been ‘consummated’ (you haven’t had sex with the person you married since the wedding), either because one of you chooses not to or is not physically capable
• one of you did not properly agree to the marriage - for example if pressure was placed on you to agree to the marriage
• one of you had a sexually transmitted disease when you married and the other person didn’t know
• one person was mentally unfit to commit to marriage at the time of the wedding
• the female was pregnant with someone else’s child at the time of the wedding and the male didn’t know that the child wasn’t his
  

Marriages can also be voidable if one of you has changed, or wants to change, their legal gender.

You can start the process of getting a ‘voidable’ marriage annulled at any time after the wedding.

The judge will look at how long it’s been since:

• your wedding took place
• you found out about the reason that you want to annul the marriage

If the judge thinks that you took too long to make the application you may not be allowed an annulment. If this happens, you may have to consider a divorce.

What to do if you think your marriage is ‘voidable’ and you want to end it

You will need to ask the court to make a ‘decree of nullity’. You can find out how to do this by following the link below.

• How to annul a marriage that's 'void' or 'voidable'