The flute in the theme music spells Morse's name in Morse code. Also, it sometimes spells the name of the murderer(!) and sometimes the name of an innocent character, to throw knowledgeable listeners off the trail.
Ailish Hurley was the bar manager of Chapter's Bar (now the Morse Bar), Randolph Hotel, Oxford. She was a good friend of Colin Dexter and was a continual source of inspiration to him, persuading him to carry on writing the Inspector Morse novels on which the TV series is based. As a mark of respect, he asked for her to be given a cameo role in the final Inspector Morse film, Inspector Morse: The Remorseful Day (2000), where she is briefly seen serving coffee to Morse and Sandra Harrison. Sadly, she died of cancer on 25 September 2005.
Colin Dexter named his two main characters after his favourite crossword compilers, Sir Jeremy Morse and Mrs. B. Lewis. Some of the other characters and places are named after local streets in Summertown (north Oxford) where Colin Dexter lives: Rawlinson Road (Ruth Rawlinson in Inspector Morse: Service of All the Dead (1987)), Aldrich Road (Phil Aldrich in Inspector Morse: The Wolvercote Tongue (1987)), Hobson Road (Laura Hobson, the pathologist in Series 8-12) and Lonsdale Road (Lonsdale College which features in several episodes).
In Colin Dexter's original novels, Morse drove a Lancia. However John Thaw, who had played Jack Regan in the 1970s series The Sweeney (1975) which featured a lot of Jaguars as villains' getaway cars, insisted that Morse would have driven an iconic British car, and never an Italian sports car. Dexter was so impressed with this reasoning that he asked his publishers to change "Lancia" to "Jaguar" in all subsequent reprints of his novels.
In the pilot movie Endeavour: Pilot (2012), which is the spin-off of "Inspector Morse" (about the young Morse's early days when first joining the police force; why it's called "Endeavour" will not be revealed here lest it spoil it for people who have yet to see it or are new to the "Inspector Morse" universe), Inspector Morse's creator Colin Dexter's love of crossword puzzles play a major factor in the solving of the murders in that first episode.