The first British series to feature a female police detective as its leading character.

Stephanie Turner auditioned unsuccessfully for the part of DI Maggie Forbes. Instead she went on to star in Juliet Bravo (1980).

At one point, the series attracted viewing figures of 18 million.

Series one featured a downbeat theme tune and title sequence setting the tone for the series. However, by the second series the theme was rearranged into a snappier more upbeat version with a fast moving title sequence using scenes from episode one.

Jill Gascoine (Det. Insp. Maggie Forbes) and William Marlowe (Det. Ch. Insp. Russell) previously played bedsit tenants and occasional lovers on the TV series Rooms (1974).