In the United Kingdom, certain marriages between close family or blood relatives are prohibited.

For Men                                    For Women

                       Blood Relatives

Mother                                     Father
Daughter                                   Son
Father's mother                            Father's father
Mother's mother                            Mother's father
Son's daughter                             Son's son
Daughters daughter                         Daughter's son
Sister                                     Brother
Father's sister                            Father's brother
Mother's sister                            Mother's brother
Brother's daughter                         Brothers son
Sister's daughter                          Sister's son

                       Others

Adoptive mother or former                 Adoptive father or former 
adoptive mother                           adoptive father
Adoptive daughter or former               Adoptive son or former 
adoptive daughter                         adoptive son
Wife's mother                             Husband's father
Wife's daughter                           Husband's son
Father's wife                             Mothers husband
Son's wife                                Daughter's husband                                
Father's father's wife                    father's mother's husband               
Mother's father's wife                    Mother's mother's husband
Wife' father's mother                     Husband's father's father
Wife's mother's mother                    Husband's mother's father        
Wife's son's daughter                     Husband's son's son
Wife's daughter's daughter                Husband's daughter's son
Son's son's wife                          Son's daughter's husband
Daughter's son's wife                     Daughter's daughter's husband

"Brother" and "Sister" include half-brothers and half-sisters. If in doubt consult the minister or superintendent Registrar.

Relations who can marry

The Marriage Act of 1986 allows certain relatives to marry. Marriages under the Act may only take place in a civil ceremony under licence, not in church by banns.

Step Relatives

Both partners to the marriage are at least 21 years old at the time of the marriage and the younger partner must not at any time up to the age of 18 years old lived in same household as the older partner.

Relatives-in-law

Relatives-in-law may marry providing both partners are over 21 years old at the time of the marriage and the former spouses (in either or both the cases must be deceased)

For Men                                   For Women

Daughter of former wife                   Son of former husband
Former wife of father                     Former husband of mother
Former wife of father's father            Former husband of father's mother
Former wife of mother's father            Former husbund of mother's mother
Daughter of son of former wife            Son of son of former husband
Daughter of daughter of former wife       Son of daughter of former husband