The first three series end with the same line of dialogue: "Now what?"
Writer Neil Cross said that DCI John Luther is actually a combination of Sherlock Holmes and Columbo (1971); he takes the intelligence and ability to solve crimes from Holmes and the introverted detective formula from Columbo.
Over the 5 seasons Luther drives 4 different Volvos although 2 have the same registration plate.
Massive Attack performs the theme songs for both Luther and House. Both lead characters are based, to a degree, on Sherlock Holmes.
Perhaps surprisingly, considering its nature and dark, violent stories and visuals throughout the entire original run, the series was broadcast at the relatively early 9pm time slot. In 2021, the UKTV's "Drama" channel ran the entire series back to back weekly, also at 9pm. By contrast many other international broadcasters ran the show much later in the evening, with Ireland's RTE running it 'uncut' in the overnight slot, to avoid the risk of any children seeing it. The much later slot also gives the series more of an 18 rating feel, especially with episodes back to back in double bills.