AS A rule, true crime documentaries tend to the exploitative, the lurid and the grubby. A dozen such films already exist about Peter Sutcliffe. But The Yorkshire Ripper Files: A Very British Crime Story, is not another.

Showing across three consecutive nights this week, director Liza Williams’s documentary is a sober, serious, almost forensic examination that not only sets the case firmly in the larger social context of its times, but convincingly argues that it was precisely that context that allowed Sutcliffe to go on attacking and killing women for as long as he did between 1975 and 1981.

At the heart of the series lies one question: did Britain’s attitudes towards women in the late 1970s, particularly as held within the police force, allow Sutcliffe to evade justice and continue killing long after he could have been caught?

The series provides compelling evidence to support the thesis. In particular, Williams focuses on the popular image that grew up around the initial murders in Leeds – that Sutcliffe was “on a mission to kill prostitutes” – and how that idea intertwined with wider attitudes about sex workers – the idea that these women’s lives were less important, that they somehow “deserved what they got”. Time and again, in the staggering wealth of archive footage, we encounter investigating officers saying things like: “Most of his victims have been of somewhat dubious moral character...”

Williams explores how such victim blaming had a direct influence on the progress of the investigation, by highlighting how the police consistently dismissed the crucial evidence of women who had survived attacks by Sutcliffe, but didn’t fit their “prostitute killer” theory – despite their assaults bearing all the same hallmarks.

For example, Tracey Brown was attacked by Sutcliffe in 1975, two months before he killed his first known victim, Wilma McCann. But when, in 1977, Brown pointed out to police that her original description of her attacker closely matched the “Ripper” photofit that had just been provided by another surviving victim, Marilyn Moore, her evidence was discounted, because she was a schoolgirl when she was attacked, and therefore, by their logic, simply not on the murderer’s radar.

The most shocking illustration of this kind of thinking comes when Williams examines coverage of the 1977 murder of 16-year-old Jayne McDonald. Unable to make her fit their accepted profile of a “Ripper” victim, newspapers actually framed the killing as a “terrible mistake”

on the killer’s part. A jaw-dropping open letter from The Yorkshire Evening Post reads: “How did you feel yesterday when you learned your blood-stained crusade against streetwalkers had gone so horribly wrong? Your vengeful knife had found so innocent a target?”

Even more telling than the archive material, however, is how we can still hear the same prejudices and judgemental attitudes persisting in new interviews Williams conducts with some of those involved in the case back then.

This, though, perhaps shouldn’t be such a surprise. As recently as 2006, when a serial killer murdered five people in Ipswich, most media coverage constantly presented his victims as sex workers first, young women last.

Williams, who is in her mid-thirties, wasn’t alive when Sutcliffe was attacking and killing woman, yet she does a superb job of evoking the period, the particular darkness that clung to the air. In some ways, watching the old footage makes it all seem like another world. In others, it feels like the day before yesterday.