Impressive footage of a volcano eruption used in the BBC series Patagonia: Earth’s Secret Paradise has been revealed as fake.

According to The Observer, the BBC admitted the scene was created by merging two separate eruptions from two separate volcanoes together - one from 2011 and one from 2015 - even though the programme suggested the eruption was a single occurrence.

The programme, first broadcast on September 25, displays the Calbuco volcano in Chile. The footage shows, above the volcano, a “dirty thunderstorm” - which is when lightning is visible in the ash cloud of a volcano.

But the corporation admitted the lightning’s presence was digitally added, having been captured in 2011 above another "nearby Patagonian volcano".

Following the programme's broadcasting, BBC Earth shared the clip on Facebook – resulting in over half a million shares. According to the corporation themselves, the clip went “viral”.

Be amazed by a super-charged volcanic ash cloud sparked by lightning.#PATAGONIA Posted by BBC Earth on Monday, 28 September 2015

Following the revelations Tuppence Stone, the programme’s producer wrote a blog post explaining: “[Dirty thunderstorms] can be difficult to see with the naked eye or be captured on a single camera.

“Our aim was to represent the stunning visual spectacle of an eruption. We took time-lapse images from the Calbuco volcano filmed in early 2015 and the lightning shots were superimposed onto the erupting cloud."

In a statement, the BBC told The Observer: “In order to show viewers the extraordinary spectacle of a dirty thunderstorm with lightning flashes that would be impossible to capture in a single camera, a composite image was put together from footage from two Patagonian volcanoes. However, we recognise that this should have been made clear.”

In 2011, the channel faced criticism after it was revealed that footage of new-born polar bear cubs, shown in Frozen Planet, was filmed at a Dutch animal park — and not the Arctic.