As he revisits his career in a new four-part series, TV’s top documentarian looks back at his evolution from accosting cult members to making films on eating disorders and dementia It is a strange feeling looking back at a much earlier version of yourself on television, a queasy mixture of recognition and distance, approval and shame, and above all an inescapable question: who is this plonker? Bespectacled, gawky, socially awkward and only 23 years old, I had been a surprising choice as a correspondent on Michael Moore’s TV Nation, a US network show where I stumbled around the wilds of America meeting extremists of various stripes: klansmen, cult members, sexual adventurers. Later, based on these segments, I landed my own TV series, Louis Theroux’s Weird Weekends . For some reason the BBC had insisted on putting my name in the title. Watching some of my early efforts again recently, with the distance of two decades, I couldn’t help passing judgment on the journalistic competence on d...