Episode 6: The Future of the Thames

0:01I think often when people consider the Thames, they think of central London, that classic sort of EastEnders shot over the river. But the fact that it starts in Gloucestershire, the longest river in England, and covers 13 ,000 square kilometres, I think the variety in the Thames is incredible. For many of us, the Thames creates an image in our minds. The river flowing under Tower Bridge, the bend at Westminster. but across the series we followed a different Thames, a river that begins far from the city, that supplies drinking water, supports wildlife and absorbs pressure from everyday life, farms and industry.

0:41We've heard from those whose families have relied on it. Since day one really it's been part of our family, it's been part of my blood, part of my heritage. From campaigners. If you go to a pristine stream it gladdens your heart, it's a beautiful thing And so that's what we're pursuing. We're pursuing that for all our rivers. From those who manage it. We are all custodians in how we look after the Thames, how we protect it and make it the healthiest river it can be. From the politicians demanding change. I mean, come on, there's something seriously wrong with the system. And from the scientists trying to understand what the river is telling us.

1:17If we can drive down nutrients, drive down the pollutants and improve water treatment and agricultural sources, I think that would be an amazing outcome.

1:31Lucy Tobin: Throughout the series, we've asked a simple question. How healthy is the Thames today? The answer has never been simple. The Thames is cleaner than it once was, but it is not clean enough. It's alive, but under pressure. This is Thames Unfiltered from The Standard in association with Thames Water I'm your host Lucy Tobin, business journalist and author So far we've looked at the river, the science, the sewage system and the infrastructure built to protect London Today, in our final episode, we look to the future What will climate change and population growth mean for the Thames? How should the river be protected in the decades ahead?

2:21And who has the power and responsibility to make that happen? But first, Westminster.

2:32Today, responsibility for water is scattered across four different regulators. The result is confusion, duplication and regulatory gaps. We will change that. On January 21st, 2026, Emma Reynolds, Secretary of State for the Environment, Food and Rural Affairs, or DEFRA, made an announcement in the House of Commons. The paper lays the groundwork for our upcoming water bill and puts us on a new path. A path where water companies act responsibly, where customers get the service they deserve, where investors can invest with confidence, and where there are clean rivers, lakes and seas that we can all enjoy.

3:12Lucy Tobin: The government says the way water is regulated in England is too fragmented. Its water white paper, based on findings of an independent commission, promises a reset, new legislation, clearer responsibilities and changes to the way rivers, lakes and coastal waters are protected. But there is one question it doesn't settle. Who should own and run water companies themselves? Lib Dem MP Sarah Dyke, then Labour's Emma Reynolds, discuss. Madam Deputy Speaker, why does the government refuse to address the failed ownership model that has allowed pollution, underinvestment and profiteering to persist for decades?

3:57If it involves whole-scale nationalisation, given that these are private companies, then that would cost around£100bn and would be legally complex and take years of wrangling through the courts. My focus is on improving the status quo, on ensuring that we are tackling levels of pollution, which he rightly says are still happening. That phrase matters. Improving the status quo. Because for some campaigners, the status quo is not something that can be repaired. It's the root of the problem. Here is Ash Smith, a voice you've heard throughout the series and co-founder of Windrush Against Sewage Pollution, or WASP.

4:39For him, the problem is not only performance, it's structure. We all of us have to drink water, use water, use the toilet, and we can't go to another company and say we're going to go to another one. We can't do that. There are monopoly companies that are exploiting us. The government has rejected wholesale nationalisation, but the argument about ownership is not going away. Here's Liberal Democrat leader Ed Davey. We're determined to turn this round and won't be fobbed off by ministers or regulators or industry spokespeople. In 10 years' time, do you think the quality of the Thames will be better or worse?

5:16I'm determined that it's better. And if this government doesn't, it will make it another big issue in the next general election. But ownership is only one part of the question. For others, the future of the Thames depends on something more practical. How the whole catchment is managed, from the smallest tributaries to the river through London. One prominent voice is Joe Bradley of Stormwater Shepherds.

5:46When I used to work in pollution prevention at the Environment Agency, we tended to try and fix a river from the top down. And that makes a lot of sense. And for the Thames, it makes an enormous amount of sense because you start at those top tributaries, you fix the wastewater treatment works, the little wastewater treatment works, they're very often out of date. You fix those, you work with farmers, you pick up some of those small industrial discharges, you work with people, you offer grant funding, whatever, and you fix them. And that way you're sort of cleaning the river from the top down. It's a little bit like cleaning your dog when it's been in a muddy puddle.

6:19You start at the head and you hose them down the body until you reach the feet. And that's how we used to do pollution control in England and Wales, at least where I worked. And we've lost that because of the Water Framework Directive, we've lost that focus and it's a damn shame. The government white paper promises more local partnerships and localised funding. In fact, local is mentioned 22 times in the document. That local focus is close to what Joe Bradley wants to see. Across the Thames catchment, you've got little gangs of volunteers everywhere who are absolutely passionate about making their river cleaner and given the resources and the tools and the agency, they can start to do that.

7:02And I think that's because the bit in the city is so damned hard and it's going to take an enormous amount of money and time. Let's at least get the rest of the catchment clean and then focus on the city with all our leftover energy, time and money as time unfolds.

7:20But before anyone can claim the Thames is improving, there's another question to tackle. How do we measure river health in the first place? I would argue that if the river ecology is healthy, if the biodiversity of the fish, the insects, the algae is good, then the water quality is fit for purpose. In episode two, we met Professor Mike Bowes from the UK Centre for Ecology and Hydrology. His argument is, river health cannot be understood through one number, one chemical or one result. It has to be judged by the life the river can support. Sometimes I think we're saying that a river is not healthy because there might be a metal or an organic compound that is present in too high a concentration.

8:10But if the otters and the fish and the insects are happy, then maybe we shouldn't be worrying about that particular compound. In the future, I think we all want to see the same thing. We want to see improved biodiversity cross our river basin. We all want our children to be able to go paddling in the Thames and use boats and go swimming and things. It's a vision few would argue with, but protecting that future is becoming harder. Two pressures keep coming up again and again, climate change and population growth. These will affect the river hugely. 15 million people are living within the Thames catchment That's a fifth of the whole of the UK population all crammed into this relatively small area.

8:59Lucy Tobin: The Thames catchment is already a relatively dry region and changes to water levels, as well as higher temperatures, mean far less dissolved oxygen. That's the crucial life ingredient for fish, insects and other aquatic life. As summers get hotter and the water holds less oxygen, that becomes a serious risk. We see that whenever the water temperature in the Thames goes above 20 degrees, we get this huge proliferation in blue-green algae numbers. This type of algae really respond to high water temperatures. Blue-green algae thrive in warm, slow-moving water. In large blooms, they can harm aquatic life, as well as posing risks to people, dogs and other animals.

9:49The Thames is especially vulnerable because in many places it no longer behaves like a free-flowing river. The River Thames and a lot of its tributaries are heavily modified. There's a whole series of weirs and locks along the entire Thames. So it's not a naturally flowing river. It's in effect a large canal almost. It's whole sections of very slow-flowing impounded water. It means that algae that is in the Thames doesn't just get washed out to sea. It can stay within the Thames for a long time and therefore it can really build up high concentrations. So river health is not only about what's in the water.

10:28It's also about the amount of water and how fast it moves. That depends partly on the weather, but partly too on us. Every day, the average Thames water customer uses 143 litres of water. We are using the water for drinking, washing, flushing our toilets. It's a huge amount of water that is being released from our houses. It goes through the sewage treatment works, is treated, but ultimately it goes into the river. And that actually supports a lot of the flow in the river.

11:02Lucy Tobin: If we take too much water out in the much hotter summers that are predicted, it will create a cascade of problems. Less water in the Thames and it will slow the flow down Causing it to heat up, stimulating algal blooms And starving the river of even more dissolved oxygen In a bid to stave off some of the dangers Thames Water needs to both reduce the amount of water lost through leaks And find new sources of supply Neville Muncaster is Thames Water's Strategic Water Resources Director rector. We've got two plans. Firstly, we've got to reduce what we waste and reduce what we use. So we're working very hard to reduce leakage.

11:49First instance, you know, that's on us. We've got the biggest investment programme going now at Thames for over 150 years where we're starting to replace our networks. We need to make sure that we have less water leaking from our pipes because then we can keep it and use it for water supply.

12:04Lucy Tobin: More than a million smart water meters installed across the catchment give a much clearer picture of when Londoners use water and how much. This is everyone's responsibility. Leakage is ours, consumption is everyone's and it's really important that we look after every drop of water we've got. Thames Water is clearly keen to put responsibility on the public. But the scale of the challenge means behaviour change alone will not be enough. And the smart meters are really important. They're telling us great information such as we know that on a hot day when the temperature goes above 25 degrees, everyone uses about 25 % more water because they're watering their gardens.

12:43So we've got to start to look at that and then say, if we're in drought, maybe that's something we have to give up or cut down because it's really important that we save the water we've got. So reducing demand is great, reducing leakage is great, but that only gets about 80 % of the problem solved. So what are we about the other 20 %? We're going to need more resources in the future. And that is what we're now working on.

13:02Lucy Tobin: One of the biggest proposed answers lies not in London, but near Abingdon in Oxfordshire. Proposals for the White Horse Reservoir would see it take water from the Thames in wetter months so it can be released back into the river when conditions are dry. Supporters say it's essential for future water security. Opponents say a vast new reservoir built across farmland would have major consequences for the local landscape. We need to take water out of the Thames in the winter, when it's got lots of water in it, and hold it there. And then in the summer, when we're dry, and if we need the water, we can release it back into the Thames.

13:41The reservoir is going to be the second biggest in the United Kingdom. It's going to contain around 150 million cubic metres of water. So it's big in scale, but really important, because it will provide a vital resource for the whole of the southeast. By having the additional storage, yes, it makes us resilient in droughts, and the reservoir will give us resilience up to a one in 500 year return drought, which is a rare event and that's why it's going in there. But it also allows us to ensure that we don't over-abstract from the areas and we keep them flowing and that's really important for wildlife.

14:12But the location is problematic and the cost substantial. We're currently pricing the reservoir around between£5.5 and£7.5 billion. Excitingly we've just put contracts out for the main construction works. So this is a big project. We think about 1 ,800 jobs will come locally from the back of this during construction and provide lots of services to local businesses and lots of work for local businesses as well.

14:37Lucy Tobin: Because of its scale, the project would go through the development consent order process, meaning the final decision sits with central government rather than the local planning system. For now, major water infrastructure has political momentum behind it. The government's white paper identifies new reservoirs as part of the national response to water scarcity and praises the Tideway Tunnel. But for communities affected by projects like Whitehorse, the question is not only whether new infrastructure is needed, it is who pays the price for it. Not just financially, but locally and environmentally.

15:19alongside the reservoir we've got two or three other schemes that we're looking to building more resilience for our water supplies in london the first of those is a new abstraction from the river at teddington which is basically taking water out of the thames as available and moving it to the northeast of london to provide additional water supplies in drought to the northeast but actually that provides our big treatment works at copper mills which again goes on to supply the city so these are big projects that we're sort of developing there are more to come over the next five years. But this is really to say that, you know, we've got a whole programme of infrastructure improvements, new infrastructure, new investments required that will ensure that we sustain the resilience in London and the South East for future years.

16:04Lucy Tobin: But securing the future of the Thames is not only about storing more water. It's also about what happens after water leaves our homes, streets and businesses. Across the Thames water region, hundreds of wastewater treatment works are under pressure Campaigners and researchers have warned that many sewage plants are already strained from today's population, let alone tomorrow's Professor Mike Bowes wants to emphasise the progress that's been made The research I do proves that the massive improvements that we've seen are due to improvements at the sewage treatment works and it's predominantly from the sewage streaming works and it's not due to changes in agricultural practices and things like that.

16:50But I would like to say that there's still a long way to go. Clearly, sewage spills are never harmless. But Mike's research shows their impact depends heavily on timing, flow and conditions on the river. Thameswater are completely oblivious to this, but we've been monitoring upstream and downstream of quite large sewage works. So we did this for about three months in winter and there was a lot of storm events, a lot of rainfall, that the sewage works became overwhelmed and had to release untreated but diluted sewage effluent into the river. We were expecting to see huge impact. We could barely see anything.

17:29The flow in the relatively small stream was high enough to dilute the pollution.

17:34Lucy Tobin: In winter, high flows can dilute pollution, but in hotter, drier summers, the same amount of sewage could be far more damaging. The pollution inputs from our wastewater treatment works will be more concentrated because there's less flow in the river to dilute them. If they're spilling because there's a failure of the sewage works and the flow is quite low, that probably is disastrous. We've not measured those yet. We might do in the future. And even if more sewage is treated, another challenge is coming into sharper focus. Some pollutants are not removed by conventional wastewater treatment at all.

18:16Catherine Head is from the Zoological Society of London, or ZSL. They're referred to as chemicals of emerging concern because we just don't really know enough about them. We don't know necessarily where they occur from. We don't know their fate. We don't know what the environmental impact of them are. things like antibiotics and pharmaceuticals, pesticides, and we're finding these things in our waterway. Two pesticides called fipronil and amidocloprid have been banned for agricultural use, but are freely available as flea treatments for our cats and dogs. Of course, flea treatment on one dog doesn't matter, but hundreds of thousands of dogs having these flea treatments and then they're bathed and it washes into our water and down our drains.

19:03And those chemicals are, they're toxic, you know, they're toxic to our aquatic life. They may be carcinogenic, they may be endocrine disruptors. So endocrine disruptors are things which mimic our hormones. These are areas that just really need more research and understanding so that then potentially, you know, legislation and policy can be acted upon and help to continue to clean up our waterways.

19:31Lucy Tobin: Conservationists like Catherine are hoping for legislation and more importantly, government funding for more research in the upcoming Water Reform Bill. It's a once-in-a-generation opportunity to be able to influence what's going to go on with our waterways in years to come. That phrase, once-in-a-generation, is important because across this series, the Thames has had many faces. It's been an industrial river, a working river, a polluted river, a recovering river And now a river under new kinds of pressure Which brings us back to where we began Blackfriars The Thames is still moving Past Parliament, through the city built around it And out towards the estuary where the river meets the sea We've looked at the Victorian system first built to deal with London's poo The modern tunnel designed to relieve it And the homes and businesses flooded by Thames water's failures How healthy is the Thames today?

20:37Lucy Tobin: It's complex The Thames is healthier than when it was declared biologically dead But it is not clean enough And its future will depend on more than one company One piece of legislation or infrastructure It will depend on political will, sustained investments scientific data and public involvement. The Thames isn't just scenery. It's London's drinking water, a vital animal habitat, a working river and a measure of how seriously we take the environment around us. The river reflects the city it runs through and its future will be shaped by the choices being made now.

21:26Lucy Tobin: That was Thames Unfiltered by The Standard in association with Thames Water. This podcast was produced by The Standard and Message Heard in association with Thames Water with all content created under The Standard's editorial control. I'm your host, Lucy Tobin, journalist and author. From The Standard, Tori Frost is our executive producer and Vanessa Cutt is our senior project manager. from message heard Mark Kendrick is our senior producer Will Aspinall is our producer Martha Tipper is our assistant producer Lizzie Andrews and Alan Lear are our audio engineers and James Cox is our production coordinator

22:25Thank you.