A navvy was what Charles Dickens derisively called the Ninth Doctor upon their first encounter on Christmas Eve, 1869. Dickens made the comparison on the basis of the Doctor's attire. (TV: The Unquiet Dead) The Fourth Doctor called Romana II someone with "all the makings of a first-class navvy" after she correctly identified the basic formula for cement and concrete. (TV: Destiny of the Daleks)