23/10/2017 9:51 PM AEDT

David Attenborough Reveals Sadness Over ‘Tragic Sight’ Of World's Oceans

Sir David Attenborough has spoken of his frustration and upset about the state of our oceans ahead of ‘Blue Planet II’ coming to our screens.

The new seven-part series, the follow-up to 2001’s ‘Blue Planet’, uses new technology to get closer to the underwater action than ever before.

The series has been four years in the making and involved 125 expeditions in 39 countries.

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Sir David Attenborough

But Sir David has revealed that filming some scenes was a “tragic sight”, in a day and age when the oceans have never been so under threat.

“We are showing how the seas are changing and what an impact that’s having on the rest of the inhabitant of the sea and ourselves,” he tells The Telegraph.

He says the most upsetting scenes are the evidence of bleaching of coral reefs.

“Seventy per cent of coral reefs have been affected worldwide to some degree, and a bleached coral reef is a very tragic sight,” he says.

The 91-year-old broadcaster also speaks of his frustration that more isn’t being done to deal with the eight million tonnes of plastic being dumped into the sea each year.

“Plastic is not a universal disaster rather the way we dispose of it,” he says. “We should increase research to counterbalance the benefits we have acquired from inventing it.”

Last month, the BBC offered a first, breathtaking look at ‘Blue Planet II’.

Sir David narrates the five-minute film, which is made even more spine-tingling by the soundtrack, which comes courtesy of Hans Zimmer and Radiohead.

‘Blue Planet II’ begins on 29 October at 8pm on BBC 1