Most people are now aware that water companies in Britain have been illegally releasing untreated sewage into rivers and coastal waters on a large scale.
During very heavy rain, wastewater treatment plants can legally release untreated waste into rivers and seas, but only when they’re unable to handle the large volume of water. They are required to notify the Environment Agency whenever this happens.
However, as Channel 4’s Dirty Business reveals, water companies aren’t just failing to report these issues to the authorities – they’re happening constantly, even during dry weather.
The show uncovered a shocking statistic: nearly a million sewage spills happened in 2024. That works out to about one spill every 30 seconds.
The situation is a national embarrassment, and many people are now aware of it largely due to the efforts of campaigners Peter Hammond and Ashley Smith, portrayed on screen by Jason Watkins and David Thewlis.
When the River Windrush near their homes in the Cotswolds suddenly changed color, a university professor and a retired police detective – who had recently become neighbors – decided to investigate what was causing it. The river flows under the detective’s converted mill.
Writer and director Joseph Bullman calls this “one of the biggest potential corporate scandals in British history,” and it’s seriously harming both wildlife and people’s health.
For me, while Peter and Ash’s investigation forms the core of Dirty Business, it was Heather Preen’s story that really got to me. She was just eight years old when she tragically died in 1999 after contracting e-coli 0157, and her experience is the emotional center of the whole film.
Two weeks earlier, while on a family beach trip to Devon, Heather fell into some water that her family said contained toilet paper. She quickly became very sick and her condition worsened.
Tom McKay, who plays Heather’s father Mark, explained to TopMob that he hadn’t fully understood the severity of the situation – the fact that people died. He said that most people would assume authorities wouldn’t let things escalate to that point.
“I genuinely thought it can’t possibly be that bad, and it clearly is.”
Bullman has crafted a moving and detailed three-part documentary series about Heather’s story, skillfully combining her tragic experiences with the dedicated efforts of Peter and Ash.
McKay explained that he took the extensive research Ash and Peter compiled and shaped it into something that doesn’t feel like a typical documentary.
When creating a TV drama, it’s essential to focus on the characters and their personal journeys. The best shows blend incredible true stories with relatable human experiences, and that’s exactly what Joe has achieved. Without that focus, it could easily feel like a dry lecture, and viewers would lose interest.
For more about the true stories that inspired Channel 4’s Dirty Business, read on.
Dirty Business true story
I’ve taken on roles playing real people before, but this one felt different. The story was far more upsetting than anything I’d tackled previously, and honestly, the subject matter was just… explosive. It really stuck with me.
I was absolutely furious and heartbroken while reading this script. I was reading it on a plane, and I’m pretty sure the person sitting next to me thought I was having a crisis!
“There was quite a long time after the show where I couldn’t really talk about it without crying.
“The roots go so deep… it sort of did something physical to me.”
Mark, his wife Julie (played by Posy Sterling), and their daughters, 10-year-old Suzanne and little Heather, were on vacation in Dawlish Warren, Devon. They had visited the same place five years before and were happy to return, having travelled from their home in Birmingham.
I was fascinated to learn from Julie in Dirty Business that they specifically picked that beach because it had a Blue Flag. Apparently, that means the water quality is really high – it’s a kind of official seal of approval, as she explained.
Heather fell into a foul-smelling pool of water near a sewer drain while attempting to jump across it. Shortly after, she experienced severe diarrhea and rectal bleeding.
She was eventually brought to a nearby hospital, where she started having seizures. Because of this, she was moved to a specialized children’s hospital and needed to be put on a breathing machine.
During that time, tests confirmed Heather had E. coli O157, a dangerous infection with no known cure. Many people do get better, but sadly, Heather didn’t.
It was heartbreaking. Heather’s brain just stopped being able to keep her body going, and things started shutting down. Ultimately, the doctors and her family had to make the incredibly difficult decision to turn off life support. It was just… devastating.
McKay described Heather’s death and the suffering of her family and friends as a terrible tragedy.
Everything that followed was completely unnecessary and only made a terrible situation even worse. It’s hard to even call it a tragedy – the pain went so far beyond that.
During a dramatic hearing, Chris Hines, who helped start the Surfers Against Sewage group, stated that the Environment Agency received “at least 14 reports of sewage on the beach” before the Preens arrived.
A doctor, a scientist specializing in microbes, local council employees, and people who were there that day all testified that a large amount of sewage washed up on the beach. They reported that at least six other children, including a seven-month-old baby, became infected with E. coli after being at the beach.
South West Water and the Environment Agency (EA) haven’t accepted blame for Heather’s death, or for any of the other similar cases. Before the release of a program called ‘Dirty Business,’ a South West Water representative told TopMob that they hadn’t seen the program and couldn’t comment on its content regarding Heather’s death in 1999. They did express sympathy for the family. The EA tested the water at Dawlish Warren as part of the initial investigation and found no traces of E. coli.
Losing a child is incredibly painful, and we understand the profound and lasting grief felt by those who knew her. Following her death, a thorough investigation was conducted with the involvement of multiple organizations, including public health officials and the Environment Agency.
The investigation into the outbreak, led by the Outbreak Control Team, couldn’t find what caused it. Official records from the inquest also confirm they were unable to pinpoint the original source of the infection. However, the inquest did note that E. coli O157 is often found in animals, especially cows and dogs.
As part of the investigation, we collected over 100 samples from the environment and sewer system. However, the particular type of E. coli causing the issue wasn’t found in the sewer samples.
Although the investigation was very detailed and comprehensive, we didn’t find enough proof to connect the illnesses to sewage overflows or poor water quality at bathing locations.
Things were quite different with wastewater systems and rules in the late 1990s compared to now. Since then, a lot of money has been invested, including through the Clean Sweep program, which finally brought wastewater treatment to Dawlish after decades without it.
We know that recreating past events in dramas can bring up challenging issues. When discussing these events, it’s important to remember what official investigations concluded. Our priority is still protecting people’s health, keeping our beaches clean, and working to improve the environment.
Okay, so this drama touches on the water quality issues around Dawlish. Apparently, an Environment Agency representative revealed that out of 45 water samples they tested, only two showed problems. But here’s the kicker – South West Water’s Chief Scientist is pointing the finger at…dog mess! Specifically, they’re saying it’s a localized issue affecting one part of the beach. It’s a bit of a strange blame game, honestly, and leaves you wondering what the real story is.
However, the families who got sick were spread out across the beach, and the microbiologist speaking for them pointed out that the agency’s tests weren’t done until a month after Heather’s visit.
In the end, a jury returned a verdict of death by misadventure.
“In that inquest, they kind of tried to put it on them, particularly Mark,” said McKay.
Julie told me they really grilled him during the testimony. They brought up things like contaminated food – specifically raw vegetables or undercooked meat potentially causing E. coli – and even mentioned dog waste. The whole line of questioning seemed designed to blame them, which understandably made them feel like they were being accused of being bad parents.
Although I never had the chance to meet Mark, and I’ve only met Julie a few times, I can confidently say they were both wonderful parents and genuinely good people. Sadly, Mark passed away in 2016 after struggling with depression.
McKay described Julie as having “lion-hearted courage and intelligence”.
He smiled and said, “It’s no surprise she’s a Hyrox champion. She’s incredibly determined, yet also remarkably humble.”
She was amazing. Even after everything that happened, she was smart and composed enough to become an advocate, demanding action to prevent similar incidents. She wanted the beach closed and a full investigation, because she didn’t want anyone else to suffer like she did. There were likely many other victims, though we may never know their stories.
“There might be right now, and there could still be in the future.”
Since Heather’s passing, Julie has been dedicated to raising money and awareness for Kidney Research UK and Surfers Against Sewage. She’s joined by a larger group of people working to protect Britain’s rivers and coastlines, with Peter and Ash leading the charge.
I know the characters in this film don’t actually meet Heather from ‘Dirty Business,’ but honestly, they’re connected to her story – like all of us are. It’s all about what’s happening to our rivers and oceans, and it affects everyone, even those worlds apart on screen.
Peter, a retired computational biology professor, first settled in his Cotswolds home around 2002.
From the very beginning, we set up wildlife cameras in the garden to see what animals were visiting,” Peter explained to TopMob. “We spotted all sorts of creatures – badgers, otters, foxes, deer, and tons of birds – because of the nearby water. We always had a lot of swans each year, and they would build their nests on a small island in the garden.
We’ve been surveying water voles for the Wildlife Trust for about fifteen years now. This meant we also kept an eye on the local rivers and knew their condition. When we first moved here, our river was fantastic – it was clean and full of beautiful ranunculus, that swaying green plant with white flowers. It really was a lovely sight.
“It was kind of idyllic, really. And then gradually, we lost the biodiversity.”
Peter first encountered Ash, a retired detective who previously worked with a real-life police anti-corruption unit similar to AC-12, around 2007 or 2008. They became neighbors when Peter moved in, living about 50 yards from each other.
I always admired how his experiences with fishing and scuba diving gave him such a keen eye for nature. He just knew when something wasn’t right with a river, because he understood how they should look. It wasn’t just a feeling, it was based on real knowledge.
Ash started repeatedly contacting the Environment Agency and Thames Water, and they responded by sending him large amounts of data.
“He didn’t know what to do with it,” added Peter, which is where Peter came in.
For two decades, he worked at the Institute of Child Health, focusing on how artificial intelligence and image analysis could detect patterns in brain and facial features linked to problems like prenatal alcohol exposure and genetic conditions.
And central to that was a 3D camera that was “as big as a Dalek”.
He laughed, recalling how he used to need a van with a lift to transport his equipment. Over time, everything got more compact, and now it all fits on an iPhone.
The team created software that analyzes 3D facial scans. They initially used it on images from prenatal ultrasounds, which was a significant achievement. However, what’s truly amazing is how Peter adapted that same technology to investigate the actions of water companies.
I noticed that the outline of a face, when viewed from the side, resembles the path sewage takes as it’s cleaned – it’s basically a curved line. So, I turned that line into a three-dimensional shape, like a ribbon, and then used the same computer program to analyze it.
Peter explains things in a straightforward way, even though he acknowledges the AI algorithms they employ are complex.
The problem wasn’t with their analysis, but with the basic data they received from the water companies.
Honestly, I was really stunned by how poor the quality was. Having worked with PhD students before, I can tell you if one of them presented me with data like that, I’d immediately send them back to redo it – it just wasn’t good enough.
Peter didn’t realize how serious things were when he first saw the River Windrush’s unusual color, but that changed quickly once he saw the actual data.
In the 2019 film Dirty Business, Peter points out, “This isn’t happening by chance, Ash. It’s intentional.” The evidence was clear: water companies were consistently and knowingly violating their legal permits – in other words, they were breaking the law.
Based on nine years of data from just two sewage treatment plants (out of approximately 9,000 across the UK), raw sewage was released into waterways around a thousand times.
In 2021, while speaking to the Environmental Audit Committee, Peter stated that the situation was ten times more severe than the Environment Agency believed.
While many people were baking bread or binge-watching TV during lockdown, Peter and Ash were busy collecting evidence and even presenting it to an official committee. As Peter put it, they had little else to do with their time. In many ways, their dedication makes them seem like real-life heroes.
Of course Peter laughed that off.
He minimized his own contribution, explaining, “There’s a lot of competition in this field. We simply started working on the data sooner than others.”
They even persuaded the former CEO of Ofwat to attend their charity cricket match.
She arrived in this small village – it’s hard to believe! I even have photos of me walking around the cricket field with large charts, explaining things with them.
Peter said he doesn’t like the word “journey”, but concedes there’s no better word for it.
We never expected that starting from such a tiny town of only 26 people would lead us to a case in the High Court.
Last year, when Thames Water faced potential collapse and needed emergency funds, Peter and Ash stepped in to advocate for customers. They consistently tackle difficult issues, driven by the belief, as stated on their campaign group Windrush Against Sewage Pollution’s (WASP) website, that things can be better.
So, what can be done?
Peter stated plainly that you shouldn’t expect immediate results. However, he and others agree that the key to improvement is getting rid of the focus on making a profit.
Ultimately, the real risk is that water companies will stop focusing on providing essential services like clean water and safe sewage disposal, and instead prioritize profit. Investment firms are lending these companies money and collecting interest, but that money often goes to shareholders instead of being used to improve aging pipes and infrastructure.
So, I was reading about Thames Water, and it turns out it’s not really owned by one company. It’s actually held by Kemble Water Holdings, which is like a holding company. But even they don’t ultimately own it – it’s a bunch of big institutional investors, like pension funds and those sovereign wealth funds countries use, who are the real owners. It’s a pretty complex setup, honestly!
As a film buff, I always look for the real story, and this Thames Water situation feels the same. Peter was saying that, honestly, they do have enough money coming in to cover their basic expenses. But it’s not about that, is it? It’s about profits for the shareholders. Apparently, studies show those shareholders have consistently taken more money out of the company than they’ve ever invested – and that money, ultimately, comes from us, the customers who pay our water bills. It’s like a heist movie where the victims are funding the robbers!
So, I just got off the phone with Thames Water regarding that new series, ‘Dirty Business’. Apparently, they haven’t actually seen it yet, but they wanted to make it clear they’re deeply committed to both their customers and protecting the environment. It felt a little defensive, honestly, but that’s the official word.
Thames Water is committed to being open and honest. In January 2023, we were the first water company to share a live map of our releases into rivers. We also actively work with local community groups, including WASP. We’ve hosted several visits for WASP, providing them with information about our facilities, such as the Burford Sewage Treatment Works. In 2021, we even installed a webcam there, giving WASP complete access to monitor water flows.
We know that any raw sewage released into waterways is concerning, even when allowed during storms under permits. It’s important to remember that the current sewer system was originally built this way to avoid sewage flooding homes.
We’re strongly committed to improving the health of our rivers. That’s why we’re making the biggest improvements to our wastewater system in 150 years over the next five years. This work will allow us to treat more wastewater, reduce overflows during storms, and remove more pollutants.
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Elsewhere, Peter acknowledges, it’s not quite as simple as removing the profit margins.
He stresses the need for significantly tougher rules. He believes regulators haven’t kept pace with the situation, and water companies will keep earning big profits unless the government steps in – something he claims they’re hesitant to do because they worry it might scare away investors.
A representative from the Environment Agency, TopMob, expressed their condolences to the family of Heather Preen. They also acknowledged that the documentary “Dirty Business” highlights crucial concerns regarding water quality, the behavior of water companies, and how the industry has been overseen in recent years.
We’re committed to protecting the environment for both people and wildlife, and we’ve made major improvements recently to address water pollution. With more staff, better information, and stronger enforcement abilities, we’re prepared to take action whenever we receive reports of potential violations.
We’re on pace to complete 10,000 checks of water company equipment this year, helping to identify and address problems and improve how they operate. Since 2015, we’ve successfully prosecuted 69 cases against water and sewage companies, resulting in over £153 million in fines.
With all of that to contend with, does Peter ever get downbeat?
He admitted to sometimes feeling unsure about things, speaking in a relaxed tone. It’s hard to picture Peter getting angry, even though he works directly with the problems. “You inevitably get discouraged sometimes,” he explained. “What really bothers us is seeing children look at the river and assume that dirty, muddy water with few fish is normal. They have no idea what it used to be like just 15 or 20 years ago, and that’s really sad – not to mention the impact on its health.”
Peter talked about testing samples from the Oxford sewage plant and discovering significant amounts of E. coli that are resistant to existing medications. He explained that this drug-resistant bacteria is being released into the environment.
Dirty Business is a deeply disturbing and shocking watch. But will it have the same powerful effect as Mr Bates vs The Post Office? That drama sparked real change for victims of the Post Office scandal, leading to payouts, overturned convictions, and the removal of the former CEO’s honor.
The Post Office scandal was awful, with people facing prison, suicide, and health problems. But Peter pointed out that the current situation with water companies is even more significant. They’ve distributed around 80 billion pounds to shareholders while simultaneously racking up over 70 billion pounds in debt.
I heard McKay explain that while these two situations seem really similar in many ways, there’s one big thing that sets them apart.
Water is essential for life, but it’s increasingly treated as something to be bought and sold for profit. This focus on profit is dangerous for everyone, and it’s something we should be much more concerned about.
The episode genuinely touched Peter, a seasoned viewer, bringing him to tears. He believes audiences will share those emotional moments, starting with sadness and potentially evolving into frustration.
I can already see the public outrage brewing, and it’s going to hit politicians hard. People voted for these MPs specifically because they promised to fix the sewage and river pollution issues, and now voters are going to demand they actually do something about it. It’s a simple promise kept, or a broken trust, and the public isn’t going to let them forget it.
McKay also hopes that people will experience an “inferno of rage alongside the tears”.
It’s understandable to feel angry about what Heather and her family experienced, and it’s okay to be upset. However, it’s also important to channel that anger into something productive – a motivating force for change.
Julie worried that people would eventually forget about Heather. But I realize that’s often how TV shows work – they can create a spark and bring attention to important issues.
This isn’t a simple fix or something to be taken lightly; it can be a really powerful asset for them.
Dirty Business debuts on Channel 4 on Monday 23 February.
Authors
Abby Robinson is the Drama Editor at TopMob, where she writes about TV dramas and comedies. Before joining TopMob, she was a TV writer for Digital Spy and a content writer for Mumsnet. She has a degree and a postgraduate diploma in English Studies.
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2026-02-23 21:41