We hear plenty of debate about climate change and its disastrous potential, but the ballooning growth of the world’s population may be the most critical issue facing humankind. Chris Packham thinks so (“it’s undeniably the elephant in the room,” he says, though lack of elephants is one of its many alarming symptoms) and in this documentary for BBC Two he criss-crossed the planet to show us the evidence.

Stephen King’s novels have generated an impressive lineage of successful adaptations. This HBO treatment (on Sky Atlantic) of his 2018 novel The Outsider, developed by Richard Price and featuring screenwriting input from Dennis Lehane, is shaping up as one of the best TV incarnations.

If nothing else, you’d want to tune in to Cobra (Sky 1) for its cast. Robert Carlyle is steely and decisive as Prime Minister Robert Sutherland, his indispensable fixer Anna Marshall is played by Victoria “Queen Mother” Hamilton, and David Haig oozes bullying malevolence as Home Secretary Archie Glover-Morgan. Solid support from Lucy Cohu and Richard Dormer adds up to a substantial thespathon.

It’s an intriguing question. If a new Messiah appeared today, what kind of reception could he (if it was a he) expect? Possibly something similar to the one which greeted Jesus, according to Netflix’s new series Messiah.

Sky Atlantic is usually where you go for big-hitting dramas, so this quartet of observational documentaries is an unexpected development. Each film follows a single family over three years, and each family faces particular challenges.

Filmmaker Tom Costello’s opening question in this quixotic but fascinating documentary for Channel 4 deftly skewered the journey he was about to take us on. Was making change or finding fame more important? he asked, and by the end of the story it was crystal clear where the main protagonists stood.

An idyllic Scottish classroom full of happy children making sponge paintings of flowers with two enthusiastic young teachers – clearly, doom is in the air. Here comes that sense of dread again a little later at a ceilidh in a village hall, with everyone trying a little too hard to look happy. And it’s soon confirmed in a flash-forward to a pathologist wiping down an autopsy table.

It's the smallest lies that can bring you down. When he is asked by a detective how he got on with his family, who have just been murdered in a mass shooting at their Essex farm, Jeremy Bamber (Freddie Fox) says: “Really well. We were friends.” A quizzical look briefly scutters across the face of his cousin Ann Eaton (Gemma Whelan) who overhears.

It happened 42 years ago, but the mass suicide of 900 people at the Jonestown settlement in Guyana is still an event that freezes the blood. They were members of the Peoples Temple, the semi-totalitarian cult founded by Jim Jones, who began as a mere egomaniac but morphed into a bullying dictator convinced of his own God-like powers.

Series about fishing have become a durable mini-genre, including the likes of Deadliest Catch and Saltwater Heroes. However, this new six-parter on BBC Two brings us much closer to home than Alaska or Tasmania, and probes into the lives of the fishing families of the Cornish village of Mevagissey.