IT has been described by Sir David Attenborough as “one of the world’s greatest surviving natural treasures” - yet it is being destroyed by plastic.

Scientists have revealed they removed 25 tonnes from the remote atoll of Aldabra – dubbed the “Galapagos of the Indian Ocean”– in just five weeks.

The haul is the largest accumulation of plastic waste reported for any single island anywhere in the world.

It will cost £3.6 million –18,000 hours of labour – to clear the tuna nets, flip flops, bottles and other debris washing up on its shores, according to new research.

Turtles were watched crawling over the rubble to lay their eggs in the sand. Iconic giant tortoises are also at risk.

The animals can mistake it for food, eating caps, containers and bags and even toothbrushes.

They find red and yellow items especially irresistible, thinking it is fruit.

Lead research author April Burt, a PhD student at the University of Oxford, said: “There are the very direct and observable impacts to wildlife such as direct entanglement, ingestion and injuries.

“We also observed turtle hatchlings struggling to get through the trash to the sea and even the adult females were having to use more energy to find and dig their nests.”

But there is also a whole raft of indirect threats which could wreck the whole ecosystem.

Ms Burt went on: “Other studies have shown plastics fuel disease in coral. “Aldabra is surrounded by coral reefs and these reefs need to be as healthy as possible to face the ongoing climatic stress they are under.”

It is more than 400 miles from the nearest significant human settlement.

But its position in the ocean currents mean that every high tide brings more plastic.

Access to the atoll, part of the Seychelles, is strictly controlled for reasons of biosecurity.

Isolated from Africa by hundreds of miles of open ocean, it is the world’s second-largest coral atoll with an area of 150 square miles, including its lagoon.

However, in 2016 the idyllic paradise lost half of its hard coral cover to bleaching.

Ms Burt said: “We just don’t know how this coastal accumulation might be feeding back microplastics onto the reef.”

In March last year her team chartered a cargo vessel and removed five percent of the litter.

An estimated 513 tonnes still remain, mainly comprising buoys, ropes and nets from regional fishing - and 360,000 flipflops.

It is the first time the financial cost for removing the waste from the UNESCO World Heritage sire has been calculated.

It equates to $10,000 (£7800) per day of clean-up operations or $8,900 per tonne of litter. Co author Dr Lindsay Turnbull, also from Oxford, said: “Our research spells out the unfairness and inequality whereby small island states and islands like Aldabra are paying the bill, both ecologically and financially for actions – or the lack of them – taken elsewhere.

“As with the climate crisis, small island states are at the frontline in dealing with the impacts of actions in which they played very little part. It is time this inequality was addressed with direct financial assistance to rectify and ameliorate these threats.”