"Australia plans to dump one million tonnes of sludge in the Great Barrier Reef.

Despite strict laws on dumping waste, the Great Barrier Reef Marine Park Authority (GBRMPA) gave the go-ahead."

It's just "another nail in the coffin" for the World Heritage-listed Great Barrier Reef, which is already under stress due to climate change, according to Dr Simon Boxall from the National Oceanography Centre Southampton.

"If they are dumping it over the coral reef itself, it will have quite a devastating effect. The sludge is basically blanketing over the coral.

"The coral relies on the algae, that's what give them their colour and what helps them feed - without this partnership the coral will suffer dramatically."

Last year, Australia pledged A$500 million (£275m) to protect the Great Barrier Reef - which has lost 30% of its coral due to bleaching linked to rising sea temperatures and damage from crown-of-thorns starfish.

One of the threats listed at the time was "large amounts of sediment".