Normal for Norfolk (or NFN) is a slang term used in some parts of England for something that is peculiar, or odd.
Utilised by doctors and Social Services in Norfolk and elsewhere to depict patients of lesser intellect, some were moved to record the letters 'NFN' against the personal details of certain clients, where they were considered to be a bit strange or had peculiar habits.
The term is considered derogatory because it portrays people from Norfolk as normally being strange, or peculiar with an inference that they are in-bred.
Most areas of the country have a regional variation of NFN, e.g. in North-West England, NFS (Normal for Stoke) may be heard.
Normal for Norfolk, was the title of a BBC series, about farmer Desmond MacCarthy, trying to keep Wiveton Hall, his 17th Century manor house, going.