"When a case proves too baffling for the minds of Interpol, they turn to the talents of Department S." – from the ITC trailer for the series.

The series was created by Dennis Spooner and Monty Berman, although neither wrote any of the episodes, which were instead scripted by ITC regulars such as Terry Nation and Philip Broadley.

Department S is a division of Interpol headed by international bureaucrat Sir Curtis Seretse (Dennis Alaba Peters).

The team itself is led by American and former FBI agent Stewart Sullivan (Joel Fabiani), who takes direction from Seretse.

The living he makes writing novels affords him a hedonistic lifestyle, and he is often seen with "beautiful" women though he has no permanent love interest in the series; in one episode he mentions he is a widower whose wife was killed in a plane crash.

Jason King also serves as comic relief in the series, especially in scenes of hand-to-hand combat where he winds up being subdued as often as he prevails.

A repeat run of Department S began on ITV4 in November 2005, alongside others of a large number of similar ITC productions.

Department S first appeared in high definition on Blu-ray as a single episode on Retro Action Volume 1 released by the Network imprint on 19 September 2011.

A complete box set of the entire series was released in Blu-ray on 2 October 2017, coded for all three regions.