The series' name was devised from the inspector's radio call sign "J-B" or "Juliet Bravo" as it features in the NATO phonetic alphabet. This sign was used only twice during Stephanie Turner's tenure, both times in series 3, episode 14 "Where There's Muck" – Stephanie Turner's final outing as the series' protagonist – when Inspector Darblay initially radios into Hartley Police Station from the scene of a road traffic accident involving a lorry carrying chemical-filled drums. On all other occasions she identifies herself as Inspector Darblay in radio communication. However, from the fourth series onwards, the call sign was frequently used. The original working title of the programme was "Inspector, Ma'am," a reference to the lead character's rank and title. This title was held during the filming of the first series, but was dropped prior to broadcast. The character upon whom Inspector Jean Darblay was based held the rank of Inspector at Great Harwood station just outside Blackburn. However, the fictional Lancashire town of Hartley featured in the programme was based on Bacup.