It is an extraordinary scene. John Maloof stands over box after box after box of the belongings of Vivian Maier. They contain photographic negatives, undeveloped film, address labels, receipts, tickets and even teeth. In all, there are around 100,000 negatives and 700 undeveloped rolls of film. Soon after acquiring this material, Maloof scanned some of the photos, put them on the internet and it took off. The formerly unknown Chicago-based nanny and housekeeper became a buzz photographer, compared with greats like Diane Arbus and Weegee.

David Attenborough’s characteristically soothing narration again described the unceasing struggle for survival in the animal world. In astonishing films from all over the world, we witnessed an enormous variety of tactics for finding homes that not only provided shelter, but protection. In nature, he told us, good homes are all too rare, and we were treated to some not-so-subtle allusions to our own housing crises.

Broadmoor is not a prison. It just looks like one, as reiterated by umpteen craning shots which prowled around the Victorian red-brick exterior, assessing its brute institutional heft from every angle. For the first time, and after five years of negotiation, cameras have been allowed to document what happens inside this mythologised sanctum. Is it really the chamber of horrors of popular imagination? Is this where society’s malignantly insane are locked away for our better safety?

How odd to recall that Michael Portillo was the Thatcherite brat they loved to hate, the man whose 1997 defeat at Enfield Southgate would have caused a Twitter meltdown had the 140-character phenomenon been invented in time. Today's repackaged Portillo has blossomed in all directions, from being a stalwart on The Moral Maze and Andrew Neil's This Week to documentaries about capital punishment and mental health. You could almost suspect he had something of the Lib-Dem about him these days, Euroscepticism aside of course. 

In The Overnighters documentarist Jesse Moss found his story and pursued it with remarkable empathy, all in the best traditions of the genre. He persuaded both sides in this tale of (quiet) confrontation to trust him, and they opened up completely. Then closing minute revelations that come as a total shock take his film to a different level, turning what would have been a strong film in itself into something that will stay in the memory for a very long time.

There are moments in observational documentary that sometimes seem to rise to the drama of fictional cinema, and Ilian Metev’s Sofia’s Last Ambulance (Poslednata lineika na Sofia) has plenty such. They come when the viewer becomes in some way so engrossed in what is on screen that the standard distinctions of form seem to be lost.

The initial challenge – and there should be no underestimating the scale of it – of Nick Read’s documentary Russia's Toughest Prison - The Condemned must have been getting into a location which the great majority of its inmates will never leave. That was likely facilitated by the acquaintance between the film’s producer Mark Franchetti, the longterm Moscow correspondent of The Sunday Times, and Subkhan Dadashov, the laconic governor of Penal Colony 56: Franchetti had been the first foreigner to visit this remote prison in the Urals at the beginning of the last decade.

Cats have had a harder time adapting to humans than humans to cats, as this remarkable examination of contemporary feline habits points out. It is not always easy changing from wild animal to feline friend, as the programme put it. Nocturnal hunters now have a life in the daytime, but they are still solo rather than pack animals. While a dog will cling to his pack – his human family – the cat susses out the physical territory on its own, seeing how safe it is and where to hide if necessary.

In a house in Nuneaton, a man calling himself Stinson Hunter lures paedophiles towards exposure, shame and possible prosecution. “We set the profile that is like the rope,” he explained. “And then if they choose to put that rope round their neck and hang theirselves [sic], that is their choice. We have not pushed them.”

This excellent documentary considerably deepens the Nick Cave we know. If there is a Cave other than the spiritually and intellectually ravenous rock star with the raven hair, bone-dry wit and shamanic showman seen here, a bumbling secret identity behind the crafted persona, co-directors Iain Forsyth and Jane Pollard don’t want to know. The junkie punk whose bands The Birthday Party and the Bad Seeds once thrived on confrontation and chaos only has a walk-on part in this portrait of the artist who survived those white-knuckle, white-powder days.