I am standing amid millions of old wet wipes soaked in filth after being flushed down the loo.
They have clumped together to form a mound on the banks of the Thames, part of a “great wet wipe reef”.
Conservationists warned it has worsened in recent years as more cleaning cloths are being used.
I visited the river in Barnes, South West London, at low tide to see the shocking scale of the problem.
Debbie Leach, chief of eco charity Thames21, said: “The Thames and its tributaries are being turned into plastic rubbish dumps.
“Hundreds of thousands of plastic-containing wet wipes, discharged from our overloaded sewage system, have formed five ‘great wet wipe reefs’, which are visible at low tide.
“It really is a disgusting state of affairs.”
She told of her fears of how the cloths are damaging the ecosystems of rivers across the UK.
Debbie, who wants manufacturers to stop making wipes, said people could reduce the amount they buy and should always bin them rather than flush them.
The cloths, which are full of plastic microfibres, are blighting beaches and rivers, causing a risk to marine life and potentially ending up in our food supplies.
One study showed 75% of flounder samples in the Thames had plastic in their stomachs.
Another found nearly a third of fish in the Thames Estuary had eaten plastic.
People in the UK use 11 billion wet wipes each year, spending £500million – a booming industry that has grown by 30% since 2014.
Many of the products are marketed as flushable so it is assumed that it is safe to do so.
That leads to 9.3 million a day disappearing down loos.
However the plastics inside them linger for decades as they break down into tiny particles.
The Environment Agency also revealed raw sewage was discharged 400,000 times in England’s rivers last year.
This included human waste, wet wipes, sanitary products and condoms, all released into waterways.
Plastic menaces Darwin islands
Plastic pollution is blighting the unique Galapagos Islands far out in the Pacific Ocean.
The University of Exeter, Galapagos Conservation Trust and the Galapagos Science Center found plastic in all marine habitats at the island of San Cristobal, where animals observed by Charles Darwin helped form his theory of evolution.
At the worst “hotspots”, more than 400 plastic particles were found per square metre of beach.
Plastic, thought to arrive on ocean currents, was also found in more than half marine invertebrates –such as barnacles and urchins – studied, and on the seabed.
The study also identifies marine vertebrates most at risk from the menace.
Dr Jen Jones, of the trust, said: “These animals are a crucial part of food webs that support larger species.
“The effects of plastic ingestion on marine animals are largely unknown.”