From the Wikipedia page [1] Westminster St Margaret and St John were two parishes, which shared a joint vestry, in the City and Liberty of Westminster and the metropolitan area of London. St Margaret was the original ancient parish and in 1727 it was split to create a new parish of St John the Evangelist for civil and ecclesiastical purposes. Despite the split, the two parishes continued to be governed by a single vestry and were commonly known as Westminster St Margaret and St John.