Around 15,000 people have marched to demand an end to the "poisoning" of Britain's waterways by sewage, agricultural runoff and chemicals.
Broadcaster Chris Packham, campaigners and angry citizens were among those who attended the demonstration towards Parliament Square in London today.
James Wallace, CEO of River Action, said: "We are marching for the end of poisoning of our waters. We would like the Government to do three things - to enforce the law, to reform the regulators and to stop pollution for profit.
"And this needs to start now. We've had 15 years of inaction. They've inherited a very difficult situation with not enough money and we need to see the environment, particularly rivers, put back in the centre.
"Everything in the economy needs clean water."
Sewage spills into England's rivers and seas by water companies more than doubled last year.
There were 3.6 million hours of spills compared to 1.75 million hours in 2022, according to the Environment Agency.
But forever chemicals and run-off from farms have also put the country's rivers, lakes and coasts at risk.
Hugo Tagholm, executive director of Oceana UK, said: "Today is the culmination of decades of campaigning on water quality and the sewage scandal, an issue that not that long ago was hidden under the surface.
"New data, new public interest and campaigners have brought it to the surface. Water companies are under huge pressure [to act].
"This is the time. The new Government really needs to deliver on what the public wants."
Water companies across England and Wales are asking for bills to be made even higher than they first requested, with one company seeking an 84% hike.
The biggest water company in the UK, Thames Water, is now looking for bills to rise 53% and an average cost £667 a year by 2029/30, according to figures published by water regulator Ofwat.
Mr Packham backed calls for Owat to be "ripped up".
He also voiced disappointment at the Government's decision to slash the environment department's day-to-day spending at the budget.
The naturalist said: "I think we need a new type of Ofwat, a proper regulator that holds people to account. I think we need significant investment in those agencies that we look to to monitor and improve water quality."
"We just had a budget which didn't give them any more money so I'm not very happy about that. In fact, we had a Budget where Reeves didn't use the word climate or nature throughout. Now that scares me because while she was delivering her budget, people's lives were being lost in Valencia due to climate breakdown and extreme weather events.
"There won't be any economic growth on a dead planet".
An independent review into the water industry could consider abolishing Ofwat among other measures to reform the sector, after a public outcry over bills, bonuses and sewage pollution.
Richard Benwell, chief executive of the Wildlife and Countryside Link, said: "The message I hope the Government takes away from today is that action to clean up our rivers won't be achieved with sound bites.
"They [Government] need to drag the regulator into the 21st century and get it tough, get it working for nature. They need to superpower nature-friendly farming and crack down on farm pollution. They need to make sure that the kind of profiteering and flagrant abuses we've seen in the water sector in the past just are the stuff of history. It's that kind of big choice that we need to see change, not just dabbling in the shallows."
Union GMB also threw its weight behind the March for Clean Water.
It represents around 15,000 workers from the water industry.
Cliff Roney, GMB's London region branch Secretary, said: "[Water companies] have taken £60 billion out of this industry, the fatcats and owners. Ofwat have failed to do their duty for 25 years. What the idea now is that the general public, especially in London, are gonna be expected to pay increased water bill to compensate for all the money taken out in the first place."
"The health and safety regulations are one thing but working in this industry is a hazard. We have a number of our staff who are ill on a regular basis."
Benjamin Fallow, 11, from Sussex, attended the protest with a banner saying "water is life".
He told how it makes him feel "quite sad and angry" when he has to sit on the beach because of sewage discharges in the sea.
The year six schoolboy said: said: "I want to be part of the people stopping pollution in our waterways. It's very important that we protect our waterways. In the future, I will be the people using these waterways and trying to help them so we need the waterways there so we can do all the amazing things we get to do now like rowing and sailing, so we can do that into the future.
A Water UK spokesman said: "The March for Clean Water is right to demand change and we support its aims. We agree that the system is not working. It is too complicated, too slow and is not delivering for people or the environment.
"No sewage spill is ever acceptable, and water companies want to invest a record £108 billion to ensure the security of our water supply in the future and end sewage entering our rivers and seas.
"Ofwat have proposed cutting this by £20 billion. As a direct result, more housing will be blocked, the recovery of our rivers will be slower, and we will fail to deal with the water shortages we know are coming.
"We cannot delay upgrading and expanding vital infrastructure any longer and need Ofwat to reconsider its approach."
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