The series is full of David Bowie references:- "Ashes to Ashes" was his first UK number one single of the 1980s and features Bowie dressed as a Pierrot clown in its video. One episode also features a "Laughing Gnome" (which is the title of an earlier Bowie song).
Series One contains references to prostitution in every episode - Drake travels back as one in episode one, sees a poster in episode two saying "We are all prostitutes!", and in another solves the murder of a streetwalker. She is also frequently dressed in red, making her a "scarlet woman".
In season 2 of BBC's Ashes To Ashes, a corrupt senior police officer and a corrupt junior police officer are played by Roger Allam (Mackintosh) and Shaun Evans (Hales). In ITV's police drama, Endeavour, Allam and Hales play morally upright senior and junior police officers (Thursday and Morse, respectively)