If a person gets married in the UK and is already legally married, then they are committing bigamy and the marriage will be considered void.
Is bigamy a criminal offence?
Bigamy is a crime under section 57 of the Offences Against the Person Act 1861. If someone is caught entering into another marriage whilst still being legally married and is convicted on indictment, they are liable to imprisonment for a term not exceeding seven years. However, prosecution is not automatic.
Are there any exceptions?
The Offences Against the Person Act 181 exempts from punishment a person whose husband or wife has remained continually absent for seven years before the second marriage without them knowing that they are alive; and parties who are legally divorced.
What if a person legally married in the UK marries someone else abroad?
Being married to more than one person at a time is recognised in England and Wales if it took place in a country that allows marriages of this kind (not in the UK) and both parties were legally free to marry in this way. Therefore, if someone legally enters the UK and already has three wives under a foreign law, then they will not be considered to be committing an offence in the UK (provided they do not enter into another marriage ceremony within the UK).
However, this may also mean that someone who is legally married in the UK could potentially marry someone else abroad, as marrying abroad means that the offence of bigamy under UK law is not applicable. However, he or she may be guilty of an offence overseas depending on whether the county he or she marries in criminalizes polygamy.
The Immigration Rules state that a person should not be granted a UK spousal visa if their marriage to the UK sponsor is polygamous and there is another person living with the sponsor in the UK who is also their husband or wife. Therefore, a man married in the UK cannot obtain a spouse visa to bring a second wife into Britain.
In 2008, the UK government gave the go-ahead for husbands with multiple wives to claim extra welfare benefits, so long as the weddings took place in countries where the arrangement is legal (as is permitted under Islamic law).
Entering into a second marriage
If your impending marriage is to be the second (or third or fourth) marriage for one or both spouses, you should check that all the formalities for the dissolution of the previous marriages are in place. If the old marriage is not properly dissolved due to a technicality, you may still be considered to have committed bigamy if you go ahead with your second marriage, and the new marriage will then be void.
If you think you may be about to enter into a bigamous relationship, you should seek advice from a specialist solicitor or contact a nearby Citizens Advice Bureau for help.