A lot of this comes down to the performances: all terrific. And I mean all terrific, with such a uniformity of terrificness that you know it must have been very well directed. Stephen Merchant reveals an astonishing range of acting nuance, like a conjuror whisking the cloak off a flock of doves, and Sheridan Smith will win awards as the bereaved mother, but really everyone’s performance is perfect, from Rufus Jones as a decent bystander to Michael Jibson as a useless policeman to Memet Ali Alabora as Smith’s adoring, struggling, heroic second husband.

The genius of the show, helped along by this wonderful cast, is the scale of what it portrays, in terms of the human condition. Its power lies in its depiction of powerlessness.

Four Lives pulls focus back from its murders in quite a familiar modern style – revealing the nitty-gritty of family tragedy, as crime shows tend to these days – but then pulls back further to reveal a story of police incompetence that’s quite breathtaking, especially considering that the real-life inquests only concluded a month ago.

And then it pulls back again, to depict with agonising freshness and conviction what it actually feels like to come up against injustice from authority. This is the exquisite frustration, the enormous fear, the ghastly vertigo that has been felt by pretty much everyone in the world – not to this degree, but you will know the principle of that feeling, whether you’ve been punished by a sadistic schoolteacher for something you didn’t do, refused a doctor’s appointment for yourself or an elderly parent when you know damn well there’s something wrong, told your desperate toddler can’t use the loo by some nasty little hitler in a posh restaurant where you didn’t have lunch, or actually, God forbid, arrested for a crime you didn’t commit. Against a backdrop of this past year, with the slamming of doors on freedom, the unprecedented horror of people being told they could not enter hospitals where loved ones were dying, and authoritarianism on the rise at every turn, it has a bite which is almost unbearable.

This move from the specific to the general, from the current to the eternal, is novelistic in its scope. We understand these families’ suffering through the prism of our own experience, tiny and huge and all across society. It’s a truly great programme.