Void marriages include:
- Marriages within the prohibited degrees
- Marriages where one of the parties was under sixteen years of age at the time of the ceremony
- Where at the time of the marriage either party was already lawfully married
- A marriage where the parties are not respectively male and female
- In the case of a polygamous marriage entered into outside England and Wales either party was at the time of the marriage domiciled in England and Wales.
Voidable marriages include:
- Non-consummation owing to the incapacity of either party
- Non-consummation owing to the wilful refusal of the respondent
- Either party did not validly consent to it in consequence of duress, mistake and soundness of mind or otherwise
- Either party, though capable of giving a valid consent, was suffering from mental disorder within the meaning of the Mental Health Act 1983 of such a kind or to such an extent as to be unfitted for marriage
- At the time of the marriage the respondent was suffering from venereal disease in a communicable form
- At the time of the marriage the respondent was pregnant by some person other than the petitioner
- An interim gender recognition certificate under the Gender Recognition Act 2004 has after the time of the marriage been issued to either party to the marriage
- The respondent is a person whose gender at the time of the marriage had become acquired gender under the Gender Recognition Act 2004
A petition for nullity may be based on the grounds that the marriage is void or voidable. A void marriage never existed. A decree of nullity if not therefore needed to end it, but it is declaratory and is needed to make ancillary financial application.










