Brace yourself, it’s The Codfather, Attenborough’s greatest fishy tale

The Beeb’s proudest achievement, its spectacular wildlife documentaries presented by David Attenborough, are famous for their no- expense- spared missions — sending camera crews to the ends of the earth.

But those budgets are not bottomless. When a team is dispatched to the Antarctic or the bottom of the ocean, there has to be the guarantee of fantastic footage. Wishful thinking doesn’t count . . . which is why you never see Attenborough In Search Of Yetis And UFOs.

So when Miles Barton, a producer on Blue Planet II (BBC1), heard about the fish missiles of the Seychelles — underwater monsters that rocketed from the waves to swallow birds whole in mid-air — he didn’t charter a plane to go there straight away.

In fact, he was sceptical. It sounded like the tallest of fisherman’s tales. There was not even a single photograph to prove this behaviour existed. The fish, called giant trevallies, were real enough. But they’re surely the wrong shape for speed, more like spacehoppers than torpedoes.

Suspecting he was the victim of some Seychelles in-joke, Miles hired a researcher to quiz the locals. They all told the same story of bird- eating fish that exploded from the water like surface-to-air missiles. So he crossed his fingers and took the biggest risk of his career.

The result was the most astonishing, staggering sequence in an hour of extraordinary stories. True, we also watched a mother walrus save her drowning calf by pushing it onto an ice floe, a tusk fish smash clams on a coral anvil, dolphins surfing giant breakers, glow-in-the-dark mobula rays and the world’s ugliest fish changing sex (it was still ugly after the op).

But none of these images could top the catapulting cod, the fat flying fin. It might look like Orson Welles on a trampoline, but the giant trevally was remarkably agile in the air. Able to gauge the height, speed and trajectory of a bird, it burst upwards with its teeth bared and swallowed its prey in a snap — beak, feathers and all.

When I interviewed him last month, Miles admitted that his favourite shots were where the birds escaped, ‘twisting and flying backwards to save their skins’.

The trevallies saved his skin, too. Imagine if it had all been a myth. his colleagues would never let him forget it — his next assignment would probably be filming unicorns.

These gambles are necessary, to make the series better than anything we’ve seen yet. At 91, Sir David has no intention of recycling past glories. Wildlife cameramen say his highest praise is the phrase: ‘Never seen that before!’ — and that’s what Blue Planet II delivers.

Veteran thesps Prunella Scales and Timothy West have a different approach to their adventures.

each series of Great Canal Journeys (C4) is much like the last, because they hit on the perfect format from the outset and know better than to tinker with it. This time, the husbandand-wife explorers were on the Norfolk Broads, a stretch of waterways that they had somehow failed to visit in a lifetime of messing about in boats.

They learned how the Broads were really flooded peat diggings, and took a ride on a Victorian steam launch. Their old pal Roy hudd met them on the pier in Great Yarmouth and showed them round a theatre, pretending they had never been inside one before.

But even if they simply sat in deckchairs, they’d be smashing value. ‘I always wanted to sail round the world,’ Pru said. ‘haven’t made it yet!’ That’s the next series, then.