In the novel N or M?, Appledore is a manservant employed by Commander Haydock.
Appledore is described as being tall and middle-aged. He has fair hair and blue eyes. Tommy Beresford believes that he might be German, although he speaks perfect English.
When Tommy is at Smuggler's Rest having drinks with Commander Haydock, he makes a reference to "N or M", which causes Appledore to spill crême de menthe on Tommy's arm.
It is later revealed that Appledore is working with the German agent, N. After Tommy is kidnapped by N, Appledore comes to give him food and water. Tommy asks if his name is Fritz or Franz, but he only replies that his name there is Appledore.