An imaginary character in the novel David Copperfield
by Charles Dickens. Mr. Murdstone refers to him while talking over little Davy's head to his friends about his pursuance of Davy's mother.
"Quinion," said Mr. Murdstone, "take care, if you please. Somebody's sharp."
"Who is?" asked the gentleman, laughing.
I looked up, quickly; being curious to know.
"Only Brooks of Sheffield," said Mr. Murdstone.
David Copperfield, p. 27