There is a temptation when writing about Blue Planet II (BBC One) to simply type out the word “wow” a few hundred times; that, after all, is pretty much what was unspooling in my head as Hokusai waves glittered and twisted across the screen in extreme slow-motion. But here goes with something a little more considered.

Filming for four years, including 6000 hours of underwater footage, the BBC’s Natural History Unit has gathered wonders and horrors from the deep. In the opening episode, we saw fledgling terns snatched from the air by giant trevally, abyss-mouthed fish capable of calculating the airspeed, altitude and trajectory of birds on the wing. A single feather spiralled down through the water following one kill; a small homage to the severed leg in Jaws.

To such scenes David Attenborough brought, as ever, a moral authority and quasi-mystical air. He was present almost entirely in voiceover rather than on location; this, no doubt, is a consequence of his 91 years, yet he does not seem frail. He is a marvel, defiant, a marble giant who ages but does not weaken as if Eric Gill’s Prospero had stepped down from his niche above the entrance to Broadcasting House.

For all its beauty and vitality, Blue Planet II was full of elegiac sadness; there was an ache in its bones. A final sequence made this explicit: a walrus and her weary pup struggled to find a piece of Arctic sea ice of sufficient size to grant them rest. The thought occurred, watching this, that the technologically-advanced civilisation which allows us to record and witness these animals in such detail is the very thing which is causing their suffering and extinction.

“As we understand more about the complexity of the lives of sea creatures,” said Attenborough in his closing narration, “so we begin to appreciate the fragility of their home, our blue planet.” His emphasis on “our” spoke volumes: not pride in ownership, but rather guilt – and grief – at the destruction which we, the dominant species, wreak. Hans Zimmer’s score had its usual majestic swell, but what we were watching suggested a simpler musical form: a blues for mother earth.

From the big blue to the big hoose, Ross Kemp Behind Bars: Inside Barlinnie (STV) saw the actor-turned-documentary maker immersed in the Glasgow prison. Having spent some time in there as a journalist, I believe Barlinnie is one of the most fascinating – and troubling – places in Scotland. It would be hard to make a dull programme about it, and this was far from dull. I’m sceptical about celebrity-fronted documentaries, but Kemp is an engaging presenter, good at letting people talk. His conversation with a murderer serving a life sentence had real power. “Regrets?” Kemp asked. The answer came without hesitation: “It’s aw regret.” Interviewing a sex offender imprisoned for viewing images of child abuse, his contempt was obvious – here he seemed less a poker-faced reporter and more a proxy for the viewers at home who, no doubt, were equally sickened.

That was good telly, but I’m not sure that it advanced our understanding of paedophilia, or addressed the question of how prisons will cope with the rising numbers of sex offenders receiving sentences. Ross Kemp Behind Bars felt a bit box-ticky when it came to those wider societal issues and the deeper question of whether prison works. But as a portrait of the infamous Bar-L – a place that looms large in the Scottish psyche but is little known in reality – it was good populist television.

Creeped Out (CBBC), which began on Halloween, is an attempt at something like a Twilight Zone for tweens. The framing device of each 25-minute episode, a hooded blank-masked figure called The Curious who collects creepy stories, strains a little too hard for Noseybonk-levels of nightmareishness. There is, too, something forced about the bolted-on moral of each story: don’t cheat; appreciate your parents; take care not to get addicted to your phone, etc. Still, it’s a decent stab at raising a shudder. The first episode, set in one of those seaside towns they forgot to close down, saw Jessie strike a bargain with a sniggering Punch-and-Judy puppet, Mr Blackteeth, to help rein in her embarrassing mum and dad; unsurprisingly, it didn’t work out as she had hoped. This refusal to offer happy endings is one of Creeped Out’s most admirable qualities. That, as they say, is the way to do it.

A word, now, about The Great British Bake Off (Channel 4). A violent allergy to Noel Fielding and concerns that the show might contain traces of his trademark whimsy had dissuaded me from tuning in since its move from the BBC. Prue Leith’s imprudent early tweeting of the winner made watching the final seem even less pressing. But I’m glad I did, if only for Scouse Kate’s Gladiator-inspired spelt loaves: “That’s Maximius, Decimus, Aurelius, and, um, Stuart.” I’d like her to have won, but it was Sophie who got the thumbs-up from Paul, the tent’s silver Caesar.