Billions of individual insects made up the mega-swarm that stretched across 300 square kilometres and munched its way through 40,000 tonnes of food a day. Sir David Attenborough sounds astounded as he reveals how the battalions of crawling insects become even more devastating as they suddenly start sprouting wings and turn into voracious whirlwind. These incredible scenes of the winged pestilence destroying the landscape will be screened on Sunday (November 27) when the critically-acclaimed series focusses on desert wildlife, particularly when the tinder-dry landscape bursts into life after the rains.

Sir David explains as the camera focuses on the insects: “No creature exploits the greening of the desert more quickly or more dramatically than the locust. “Madagascar’s arid south-west has received its highest rainfall in years. Now an army is on the march, attracted by the smell of newly sprouting grass.” As the floor turns into a carpet of marching, munching insects, Sir David adds: “Locusts are normally solitary creatures but when food becomes suddenly plentiful they come together into an unstoppable force that devours everything in its path.

BBC Billions of hungry locusts caught on camera on Planet Earth 2

David Attenborough's Planet Earth II Mon, November 28, 2016 Planet Earth II: Stunning images from David Attenborough's magnificent nature documentary. Play slideshow BBC NHU/Chadden Hunter 1 of 38 An African bull elephant swishes his trunk at the carmine bee-eaters following him through the grassland of Botswana

“But this devastation is about to get a lot worse. The locusts now transform into winged adults and, with conditions as good this, they do so three times faster than normal…

They come together into an unstoppable force that devours everything in its path Sir David Attenborough

“Now they are at their most voracious and with wings they can take to the skies… BBC producers say the swarm they filmed was travelling up to 100 kilometres a day and eating vast amount of vegetation. Even though the swarm stretched across an area larger than Birmingham, it was still an onerous effort to track it down. Ed Charles, producer of the Deserts episode, explained: “Filming in Madagascar was an eventful trip on all fronts. You wouldn’t think it would be difficult to find a billion locusts, but you’d be surprised.

BBC The mega-swarm stretched across 300 square kilometres

"We went to some very remote rural communities looking for them, and one by one we all got sick because of the local street food. “The locust sequence captures one of the largest swarms that has ever been recorded on film. It’s absolutely epic and we filmed it in a way that you might not have seen before.” This comes after a Planet Earth cameraman revealed he spent three weeks in snake infested swamp to film a ninja frog. Locusts are related to grasshoppers but when they transform from their solitary to gregarious phase they become one of the most devastating creatures on the planet.

BBC The plague of insects devoured its way through 40,000 tonnes of food a day

They appear in the Book of Exodus as one of the plagues that visited upon Ancient Egypt and they continue to pose a threat to food production to this day, threatening crop loss, famine and starvation across a desert landmass that contains 60 countries in Asia, Africa and the Middle East. Although the Planet Earth 2 swarm is one of the largest ever filmed, there are reports of clouds of locusts stretching across 1,200 square km and at a density of 80 million individuals per square km.

BBC This is one of the biggest plagues of apocalyptic locusts ever caught on camera