UK plastic waste is being exported to Turkey and then illegally dumped and burned, according to a report.
Greenpeace said about 40% - or 210,000 tonnes - of the UK's plastic waste exports were sent to Turkey last year.
But rather than being recycled, investigators saw some of it dumped by roads, in fields and in waterways.
The UK is a "global leader in tackling plastic pollution", the government said - after Greenpeace called for it to "take control" of the problem.
Greenpeace's report warned Turkey was becoming Europe's "largest plastic waste dump".
The charity said it had investigated 10 sites across southern Turkey and found plastic bags and packaging from UK supermarkets and retailers at all of them.
Packaging for a coronavirus antigen test was also found, indicating the waste was less than a year old, the report said.
