Over the past three weeks, Louis Theroux has produced some of the most fascinating work of his already impressive and eclectic career. Moving to Los Angeles for a year and producing three hour long specials for The BBC entitled 'LA Stories', he’s explored three socially uncomfortable subject matters with his trademark amiable, yet pressing style.

The first episode centred on LA’s street dogs and how seemingly normal, functional members of society treat these creatures that were essentially put on this earth for companionship. From the get-go it was pretty clear that Theroux wasn’t really a dog person; whether that was a specific decision Theroux took to distance himself from these animals and their owners, doesn’t really matter. We see an aggressive dog that regularly attempts to attack him and his crew, suddenly become passive when a man who seems to be, frankly, full of shit (at least initially), inexplicably transforms the animal into a passive house pet.

Not all of the dogs were capable of such a transformation though; as Theroux himself ponders, are some maybe beyond rehabilitation, much like human beings serving life sentences for despicable crimes? When he revisits a homely, hipster couple he gets his depressing, but almost inevitable answer.

An obviously difficult programme to sit through, as heartbreaking as it was, it didn’t have a patch on the second episode in the series which featured Theroux talking to people with terminal illnesses. Watching how he posed questions to these poor people and their already half-grieving families was emotionally shattering. It was an hour of television that had the kind of impact that no piece of fiction, no matter how well written, ever could. You watched Theroux talk to these hopeful souls and hoped for a miracle alongside them; ecstatic when one took place, but destroyed when it didn’t happen for another suffering patient.

In the final episode Louis took somewhat of a tonal left turn, focusing on sex offenders and the difficulties of their reintegration back into society. This is arguably when Theroux is at his absolute best as a journalist; when he allows silence to open up uncomfortable subjects.

A female teacher who had slept with a 14 year old student; a man who wanted to castrate himself so he could live a life without both physical and mental shackles of his ‘urges’; and a chap who was trying to help all of these people - a man with a past so dark, when you find out what he did, it hits you like a kick to the chest.

Louis doesn’t judge, or offer ‘thought of the day’ observations on these people. He simply observes, ponders and digests, just as his audience does.

LA Stories is easily the best television we’ve had the pleasure of sitting through in some time. Thought provoking, challenging and utterly engrossing, it underlines Louis Theroux as a documentary filmmaker with few rivals.

Genuine, no bullshit, astonishing television.