Dennis Waterman originally wanted Denholm Elliott to play the part of Arthur Daley. Executive producer Verity Lambert disagreed.
The show was actually a slow burn success. Viewing figures for the first season were not very good, which wasn't helped by the show being delayed because of a nine week technicians strike which blacked out the ITV network, and Thames Television decided to axe the show. However, the managing director felt positive about it and pressured them to commission one more season and to repeat the first. Both of them received much higher viewing figures, and by the third season, was a huge hit. It eventually attracted around 17.5 million viewers in the U.K. at its peak (when there were only 3 or 4 TV channels), and went on to be shown in seventy countries.
The series was famous for its use of "Mockney", which sounded like Cockney slang, but was made up by either George Cole or the scriptwriters. Some expressions became so well-known they have since passed into the language, including "a nice little earner" (a profitable task), "'er indoors" (the wife), "give him a little slap" (beat him up).
In 2005, Arthur Daley was voted second favourite television character in a poll to celebrate ITV's 50th anniversary.
The series was originally conceived as a star-vehicle for Dennis Waterman, after Regan (1975), in which Waterman co-starred, had finished the previous year. Initially, George Cole's character, Arthur Daley, was more of a secondary character, finding situations for Terry (Waterman) to get involved in each episode. But the great chemistry between the two characters quickly made itself apparent, and as a result, Arthur was brought to the fore of storylines much more.