As Ozzy Osbourne puts it, “He’s just Lemmy. You just take him or you fucking don’t, and he doesn’t give a flying shit whether you do or not.” It’s this irreducible Lemmyness of Lemmy which lies at the core of the gnarled heavy metaller’s mystique. Beyond fashion, as ageless as a rock’n’roll Flying Dutchman and with a constitution seemingly forged from buffalo hide and wrought iron, Ian Fraser “Lemmy” Kilmister is surrounded by his own private myth-bubble wherever he goes.

The title could have used a bit more work, I'd have thought. No, Peter Mandelson was never "the real PM", and won't be now. As for the real Peter Mandelson, there is no evidence that any such mythical beast exists. And why hadn't Lord Mandelson become prime minister, film-maker Hannah Rothschild asked him in one of her deferential voices-off moments? Because Tony Blair and Gordon Brown had entered parliament in 1983, Peter explained with exaggerated patience, while he himself had only got there in 1992. He was stuck at the back of the queue and had to wait his turn. This being the Labour party, an organisation which makes the Titanic look state-of-the-art, his chances of speedy advancement to pole position were more or less nil. And lots of people hate him of course, though he left that part out.

This bit was at the end, but it might as well have been at the beginning. Or, really, just bannered across the bottom of the screen all the way through: "I am a performer. That is my life. That is what I am. That's it."

An English teacher in a brand-new Hertfordshire secondary school is about to lose his rag. “You said ‘relaxed, like,’” he storms at a boy. “Why like? Like what? Why do you use that expression? What does it mean?” This is 1962. It’s a scene from Our School, sponsored by the National Union of Teachers, one of four documentaries made between 1953 and 1964 by John Krish in the BFI’s Boom Britain: Documenting the Nation’s Life on Film, a project that celebrates the neglected heritage of the post-war documentary.

This first feature from Swedish writer-director Ruben Östlund arrives heavy with awards, the seasoned and decorated product of film festivals across Europe. Brutal, quirky and elegantly self-conscious, it does little to challenge the trends that have recently made Swedish cinema (Let The Right One In, The Millennium Trilogy) such hot property. The title serves as agent provocateur for the action that follows: a fractured and wilful deconstruction of group dynamics, of the pressures and “victims” of the social collective.

The recurrent image in this somewhat staid documentary is a monochrome photograph of Poe’s moon of a face with its panda-like eye sockets. Occasionally the camera moves in for a close-up on those eyes - perhaps hoping they’ll reveal something that mere biographical detail doesn’t - but appropriately enough the grim Gothic writer’s eyes are more black holes than windows on the soul, and they give nothing away. The horrors, scandals and tragedies of Poe’s life had to be exhumed from his words, and the words of those who came into his orbit.

Nowadays it’s not so easy to find a doc you can trust. Since talent shows started supplying back stories as part of an all-in-one narrative package, it’s as if everyone has learnt how to behave when there’s a camera crew around. Meanwhile, in the cutting room film-makers can be quite as manipulative as colleagues who nakedly trade in fiction. But there are some things you can’t fake. A young male troupe of cheerleaders from rough working-class south Leeds? That’s one of them.

This is the antidote to Martin Scorsese’s 2008 documentary Shine a Light, which, for all its technical excellence, depicted the increasingly senior rock band sounding pretty crap. Ladies & Gentlemen: The Rolling Stones was shot at four concerts in Texas on the Stones’s 1972 American tour, hot on the heels of the release of Exile on Main Street.

The most surreal scene in this searing, adrenaline rush of a documentary about a US platoon in Afghanistan is the sight of three soldiers dancing madly in their bunker to "Touch Me, I Want to Feel Your Body" on an iPod.