Piled up among the driftwood, scores of discarded bottles, car parts, tyres and crisp packets choke one of Britain’s rivers.

It is yet another illustration of how plastic litter is poisoning our planet.

The shocking photograph – taken in Doncaster – came as the UN’s environment chief said Britain was now leading the world in tackling the issue with the help of the Daily Mail.

Praising our campaigning, Erik Solheim said: ‘We need the Daily Mail to do that as we need to reach out to everyone, not just preach to converted environmentalists. You can see the results of the campaign because the Government of the UK are taking the global lead on plastics.

Piled up among the driftwood, scores of discarded bottles, car parts, tyres and crisp packets choke one of Britain’s rivers

‘I’m sure they believe in the campaign, there’s no issue about that, but if it is set out so clearly for people in the UK they are much more likely to support it.’

The UN chief also backed the Mail’s Great Plastic Pick Up, which runs this weekend – from May 11 to 13 – saying such clean-ups were a vital way to teach people to stop dropping litter.

He said: ‘I think this is excellent. Everyone knows we need to stop plastic at source. But clean-ups make cities much prettier and creates the attention and interest that will drive political change and in people’s behaviours.’

There has been a huge response to the Great Plastic Pick Up, with 11,085 readers registering to take part and 783 different events organised across the country.

The Doncaster photograph from last week shows the volume of litter that heavy rain swept from streets and into the rivers Don and Cheswold. Much of it became stuck in the Don aqueduct.

John Hourston, of campaign group Blue Planet Society, said: ‘This is litter that’s been thrown away. I’ve seen hundreds of pictures of plastic pollution in the UK. That’s the worst picture of plastic pollution in a British river I’ve ever seen. Many people on social media have been comparing it to a Third World country, which we traditionally associate with this level of pollution.

‘It’s come at a watershed moment, that photograph, it’s properly shocking. Hopefully it’s the straw that breaks the camel’s back and forces people to act.’

UN chief Erik Solheim parades a Mail front page

Striking an optimistic note, Mr Solheim said the world was standing on the brink of changing its attitude toward plastic.

The UN chief held up a copy of the Daily Mail at a meeting of more than 100 environment ministers in Kenya last year to praise this paper’s campaign on plastic waste.

Explaining why he cited the Mail, he said: ‘It was exactly what we needed. My main ambition working on environment in the UN is bringing the issue of plastics to the kitchen table of people.’

Mr Solheim said it was vital to bring environmental issues home to people, whether they are living in Kent, Miami or Guangdong in China. ‘The Daily Mail has a massive ability to do that, it reaches out to anyone, to bring issues home – you’re great at that, and that’s why I find it so good,’ he added.

‘We are very, very happy to be covered by the Guardian, absolutely, but we need to go beyond converted environmentalists. In the past, just a few people were asking about it. It’s now a mainstream issue in society. This is exactly what we need.’

For the past decade the Mail has campaigned to cut plastic waste, leading calls for a 5p charge on plastic bags, then switching focus to microbeads, throwaway coffee cups, plastic bottles, straws and pointless packaging.

Rubbish, Plastic and other litter floating on the river Cheswold, Doncaster, South Yorkshire

Mr Solheim praised Theresa May and her ministers for leading the way on tackling plastic poison, and backed their moves to introduce a bottle deposit return scheme.

Singling out straws, the UN environment chief called for a ban on plastics that cannot be recycled.

He said: ‘Why can’t you drink from a bottle or a glass? If every bar put up a sign saying, “If you need a straw ask for it” that would cut straw use by 95 per cent.’

n Plastic wet wipes, which are blamed for more than 90 per cent of sewer blockages, are to be banned. Tens of millions of the throwaway wipes, which are used for babies, to remove make-up and to clean homes, are flushed down toilets.

The Department for the Environment, Food and Rural Affairs said: ‘As part of our 25-year environment plan we have pledged to eliminate all avoidable plastic waste, and that includes single-use products that include plastic such as wet wipes.’