The series is set in a dystopian future in which Britain is under the grip of the Home Office's Public Control Department (PCD), a tyrannically oppressive bureaucracy riding roughshod over the population's civil liberties.

Dubbed "Nineteen Eighty-Four plus six" by its creator, Wilfred Greatorex, 1990 stars Edward Woodward as journalist Jim Kyle, Robert Lang as the powerful PCD Controller Herbert Skardon, Barbara Kellerman as PCD Deputy Controller Delly Lomas, John Savident, Yvonne Mitchell (in her last role), Lisa Harrow, Tony Doyle, Michael Napier Brown, and Clive Swift.

Jim Kyle (Edward Woodward) is a journalist on the last independent newspaper, called The Star, who turns renegade and fights the PCD covertly.

Skardon's two Deputy Controllers are Delly Lomas (Barbara Kellerman), who has an ambiguous relationship with Kyle and Henry Tasker (Clifton Jones).

The government machine is headed by Home Secretary Dan Mellor (John Savident), replaced in office in series two (supposedly through Kyle's efforts) by Kate Smith (Yvonne Mitchell).

This is made clear in one episode where the Royal Air Force (RAF) is depicted as consisting of little more than a handful of Harrier jump jets and a few dozen counter-insurgency helicopters.

It is said that in 1986 two army generals and a retired air chief marshal attempted a coup against the government but it failed and the plotters faced the firing squad.

Ordinary criminals found guilty of traditional and new economic and social crimes are prevented from clogging up the decaying prison system by having short sentences during which they are force-fed "misery pills" (via a gas mask-like apparatus that holds the mouth open), which induce severe and permanent depression and agony during their incarceration.