David Attenborough's film crew broke one major rule after spotting huge problem filming sea lions

Pop open a bottle of champagne and toast Sir David Attenborough's 98th birthday.

The legendary broadcaster has spent decades introducing us to the wonders of the natural world and letting us observe all species great and small in their daily delights and struggles.

He's also turned to urging us to do more to protect the planet from catastrophic climate change, which is wreaking havoc on these wonderous places in nature, and the impact becoming impossible to ignore for us as well.

We do have to slightly spoil that a lot of the animal voices you hear on Attenborough's shows are added in after filming, but you try fixing a pack of hyenas with microphones.

While the film crews working on his shows do some incredible work in bringing the natural world to our TV screens, Attenborough's film crew did break a big rule when they were working with sea lions.

Today is Sir David Attenborough's 98th birthday. (Rob Pinney/Getty Images)

As well as bringing us some utterly wonderous sights to behold, Sir David Attenborough's shows also don't shy away from the more gruesome and graphic parts of nature.

You'll see plenty of animals hunting each other in his shows, with beasts tearing chunks out of each other in the fight for food and dominance.

In such situations, there are things the crew can do and rules they are not supposed to break.

The cardinal sin for nature documentaries is interfering as they're supposed to let nature take its course - they might feel really bad for that old chimpanzee as he's beaten within an inch of his life, but they're not allowed to step in and stop it.

However, in the case of the sea lions the crew broke the 'no interference' rule for a pretty good reason, it was our fault in the first place.

While filming for an episode of Planet Earth III the crew went out to rescue some sea lions which had been caught in fishing nets, with series producer Matt Brandon saying they couldn't 'shy away from the impact that humanity has had on the natural world'.

In the same series, the crew also helped turtles that were exposed to heat make it to the sea.

The crew for Planet Earth III stepped in to help sea lions who'd been caught in fishing nets, as that one is our fault. (BBC)

This is not the only time that one of Attenborough's film crews have broken this crucial rule.

There was a particularly famous moment in the penguin episode of the show Dynasties, which showed that some of them had tragically become trapped in a ravine and could not get out.

With some of the penguins already frozen to death, the situation was too heartbreaking for the crew not to intervene and the crew took the 'unprecedented move' to step in and save the birds.

They dug a few steps in the ravine which the penguins were able to climb up and out to safety.

While the 'no interference' rule is pretty vital, it's unlikely that many would take issue with the filming crew digging a few steps so animals in distress could save themselves, it's a very different story to stepping in and preventing a predator from gobbling up its prey.