TV preview, Blue Planet II (BBC1, Sunday 8pm): A breathtaking exploration of life's depths

Plus: The Great British Bake Off (Channel 4, Tuesday 8pm), Great Canal Journeys (Channel 4, Sunday 8pm), Robot Wars (BBC2, Sunday 8pm), 66 Days (BBC4, Tuesday 9pm), The Balfour Declaration: Britain’s Promise to the Holy Land (BBC2, Tuesday 9pm)

Not pretty, but fascinating: David Attenborough brings us the kobudai fish (BBC)

There’s a bit of a loaves and fishes theme to viewing this week. For me, I think, the TV highlight won’t be the final of The Great British Bake Off (er, that’s the loaves bit), landmark in civilisation though it undoubtedly is, but David Attenborough’s Blue Planet II (includes fishes, obvs), and for the sheer majestic scale of its ambitions and record-breaking ugliness of the aquatic denizens we get to see up close.

Even in his tenth decade, Sir David retains a certain boyish charm and enthusiasm, still recognisably the same chap who started chasing after anteaters across the savannah in the 1950s. More than ever we need his skills as an entertainer, teacher and, most important, campaigner.

So here is again, in a new seven-part series doing what he does best, exploring life and the man-made threats to it. The Blue Planet net team spent four years organising 125 expeditions in 39 countries, filming across every ocean and over 6,000 hours underwater to bring us some spectacular footage. OK, the playful bottle-nosed dolphins are familiar enough, but what about the fighting Japanese kobudai fish? Not only are they the most grotesque-looking things in the sea, but when the female kobudai reaches a certain size and age she can undergo her very own sex change. All yours, in High Definition, for the price of the annual licence fee.

If Blue Planet II makes the case for the BBC as a broadcaster uniquely placed to do the things it does – indeed pretty much unrivalled in this respect globally – then the defection of The Great British Bake Off to Channel 4 perhaps proves the opposite. A baking show doesn’t have to be done by the state broadcaster at vast cost in licensing fees. With different presenters and contestants (obviously the real stars) the show has demonstrated that it has a durable formula that didn’t, in the end, rely on some special BBC ingredient to make the creative soufflé rise to the occasion. No doubt the winner of the contest on Channel 4 will become a celebrity of some sort, and may inspire more people to go out and make flapjacks. Which is nice, but not as important as saving life in the sea, surely?

When I was at school there sat in the library some bound set of Meccano Magazine, a wholesome sort of educational journal from the 1950s. One recurring feature centred on one chap’s adventures on a narrow boat along Britain’s waterways, and carried the headline “My Canal Journey”. Obviously, and all too predictably, the “C” has been obliterated in almost every case. So it is with a barely-suppressed childish snigger that I recommend Timothy West and Prunella Scales’s Great Canal Journeys, with that capped-up C immune to schoolboy defacement, I am pleased to say. Anyway, there’s nothing quite like the vicarious pleasure of watching two of our most talented and loved actors simply enjoying life for the hell of it. They almost make older age, with all its terrible frailties and insecurities, something to look forward to. I don’t think they’re just acting.

Robot Wars is also worth a watch. As the world moves inexorably towards true artificial intelligence – computers being able to make decisions for themselves – it is rather quaint to see a biscuit tin attached to an alternator from a Vauxhall Corsa and a kitchen knife described as a some sort of superior being, the heir to HG Wells’s vision of a planet overrun by malevolent machines. You’ll be relived to know that these generally unimpressive amateur creations have still got their silly names, and deeply flawed engineering, which comprise the charm of the show. Dara O Briain and Angela Scanlon do their best to take it all seriously and not to laugh out loud at the nerds.

Lastly, two serious historical documentaries for you on Tuesday evening. 66 Days takes its title from the period of Bobby Sands’s hunger strike in 1981, one of the many low points in the Troubles in Northern Ireland. Sands was an IRA man who was protesting his claimed right to be a “political prisoner”, a status not recognised by the UK and consistently refused by the then Prime Minister, Margaret Thatcher. Sands’s death caused riots and created another martyr for Irish Republicanism; it also led directly to the Brighton bombing a few years later, which took the lives of democratic politicians, and almost that of Thatcher herself and the entire cabinet. The irony was that Thatcher’s appearance at the Tory conference the very next day merely added to her legend and forced yet more iron into the soul of the Iron Lady.

You can take the view that Sands was a murdering monster or freedom-fighting hero, but this life – and death – mattered as a news event and a moment in history. Here we get to hear from Sands himself, via his previously unpublished diaries. A chilling reminder of what can so easily go wrong in that part of the world.

A still more important moment in history came 100 years ago when the British government, arguably, legitimised the idea of the state of Israel. In 1917 Lord (Arthur) Balfour sent a letter to a prominent British Zionist which promised a “national home” for the Jewish people. Wisely a junior member of the government of the day, Leo Amery, added a clause that attempted to protect the interests of the existing Arab population in what Balfour was to describe as his “experiment”.

Jane Corbin, a veteran of wars and the many conflicts in the Middle East, is descended from Amery, and in The Balfour Declaration: Britain’s Promise to the Holy Land she revisits the two-state solution to the Arab-Israeli conflict that was, some believe, envisaged in the declaration, and made, all too briefly, reality in the Oslo accords in 1993. You won’t be given much hope for peace, but you’ll understand a little more about this most tragic of struggles.