Fiance(e)s and proposed civil partners: If you wish to come to the UK to get married to a person who is a British Citizen or settled here, you need to apply for a visa to enter the UK. When you make the application you will be required to show evidence that your marriage or registration of your civil partnership will take place within 6 months of your arrival here.
Please also note that after coming to the UK you will be required to give notice to marry or register your civil partnership with a registrar at a 'designated office'.