As a sensitive – OK, pretentious – 14-year-old, I became obsessed by . This adolescent preoccupation was fuelled by a school science project, Greenham Common’s ubiquitous presence on the TV news and plentiful anti-bomb songs in the pop charts – the surprisingly dark likes of Frankie Goes To Hollywood’s Two Tribes, Nik Kershaw’s I Won’t Let the Sun Go Down on Me, Culture Club’s War Song and Nena’s 99 Red Balloons. And then, in autumn 1984, my teacher wheeled a teak-effect Grundig into the classroom to show us a VHS recording of Threads.

Don’t have nightmares, kids. This unflinching two-hour docudrama about first aired on BBC Two at 9.30pm on 23 September 1984.

It attracted 7m viewers, the channel’s highest ratings all week, and went on to win four Baftas, including Best Single Drama. It also entered TV folklore because , it’s only been shown twice by the broadcaster since. Now it’s getting a timely rerun, along with a radio documentary asking why it continues to haunt viewers, four decades later.

This weekend’s Archive on 4: Reweaving Threads, 40 Years On rummaged in the vaults to explore the film’s legacy and influence. With BBC Four is planning a rare TV airing next month, I decided to revisit it. Has Threads stood the test of time? Is it still as scary? And how did such a harrowing film get made and shown on terrestrial TV in the first place? The grimly fascinating story of Threads dates back to 1965, when the BBC commissioned another infamous .