The last yellow sycamore leaves spin downwards as vast beds of reeds whisper in the wind. An ancient oak stretches huge branches across the glinting water and, for a moment, London’s third biggest river looks as graceful as it did two centuries ago. Then my walk with Paul Powlesland on the banks of the River Roding collides with contemporary Britain. There is a tributary, sending a steady trickle of sewage into the main channel. A flashy new block of riverside flats, failing to provide residents with any greenery or way to access the river. Further along, heaps of fly-tipped rubbish and the recent relics of camps created by desperate people without homes: mouldering mattresses, discarded needles and excrement. Cleaning up this shunned and abused river and placing it in the hearts of those who live beside it in east London is daunting. But Powlesland, a compelling, sprite-like young barrister who not only fights for nature in the high court but devises imaginative environmental campaigns and takes hands-on direct action, is undaunted. He moved here – chugging up the Roding on his narrowboat – five years ago, and anointed himself a local “nature guardian”. He created a charity, the River Roding Trust (RRT), found other local people wanting to clean up their river, and began its transformation. There is a lot to do, but today the rubbish is being cleared, riverside trees are being planted, water quality is monitored, the companies releasing pollutants or sewage are being held to account, and developers are being cajoled into providing riverside homes that better serve the river and its neighbours. We meet beside the Roding in Barking, Powlesland in a retro jumpsuit, looking as if he has stepped from the set of Buck Rogers. He has, in fact, just stepped from an equally far-fetched scene: his off-grid boat beside moorings he built from scaffolding, and which is equipped with a wood-fired sauna and hot tub and outdoor barbecue area to tempt other boat-dwellers to join him as resident “river guardians”. He’s currently seeking more. The Roding needs local protection because it endures “pretty much all of the water quality issues it’s possible for a river to have,” he says. The river springs up near Stansted and its journey through intensively farmed Essex fills it with fertiliser and pesticides. Then the M11 and the North Circular, built on the green corridor the river creates as it meanders into the suburbs, dispatch polluted rainwater into the flow. When it reaches London, the river is struck by dreaded “CSOs”, the combined sewer overflows from antiquated sewage systems that allow rainwater and sewage to be released during heavy rain to prevent sewage backing up into homes. Finally, as the Roding approaches the Thames, it meets riverside heavy industry, potentially adding more toxins. The tide is flowing swiftly upriver on a bright morning as we begin our walk north, up steps on to a footpath beside the river. “These steps are a prime example of why you need local nature guardians and also how power works in this country,” says Powlesland. “This is a public footpath; it’s been used for over 30 years. But a developer wanted to use this area for materials storage so they just boarded it up and shut off the path. I came in with a sledgehammer and smashed it open.” I assume Powlesland is using a legal metaphor. No: the barrister hacked down the wooden hoardings. “I’m legally entitled to do it because they are blocking a public highway,” he explains. “Knowing the law helped me do the direct action because I wasn’t committing an offence – they were, and I was just correcting it on the ground.” The developer rebuilt the hoardings. Powlesland demolished them again. “Eventually they rebuilt it so strong that I couldn’t smash it any more so then I had to start local campaigning. If Just Stop Oil block a public highway, the police are there in an hour. The path here was shut for a year and a half. And this route allows the ordinary people of Barking, quite a poor borough, to access Tesco from the town centre without walking along really busy roads.” After Powlesland campaigned via the River Roding Trust, the developer eventually reopened the path. It takes us beside rubbish-strewn car parks but Powesland’s gaze is on the self-sown cherries and sycamores forcing through concreted banks. Perhaps his faith in the potential of the river to change is bolstered by his own transformation. He grew up in Surrey. His family weren’t particularly interested in nature but he realises now that he was always drawn to rivers as a boy. At the University of Cambridge, where he studied law, he was vice-chair of the Conservative Association but his politics radically shifted after he chanced on an obituary of the writer Roger Deakin, read his classic Waterlog and began wild swimming. He fell in love with nature in his 20s (various festivals helped alter his mindset, too) and began planting trees. Both swimming – despite the pollution, he swims in the Roding – and tree-planting are combined in his river guardianship, with the trust organising work-days where up to 30 local volunteers build benches and perform Herculean litter-picking tasks. But Powlesland also undertakes guerrilla planting. “See that cute little island?” he says, pointing to a patch of mud midstream. “There’s a willow I planted.” Along the bank, dozens of young willows are growing rapidly. “Imagine you’re having a Sunday out in Barking in February and you see a man in a bright pink jumpsuit poling a kind of Venetian gondola, a giant muddy raft full of willow saplings, downriver, like a shit Cornetto advert. I just pop them in every bit of mud you see.” Powlesland held a willow-planting birthday party three years ago where the river bends prettily around a large reedbed. He jumps over the wall and into the swamp. “Look at the size of that trunk! It’s just incredible!” A three-year-old willow’s trunk is already as thick as a Jack Grealish calf. “I’ve never climbed a tree I’ve planted before,” says Powlesland, and shins up three metres. “There’s few greater things in life than being able to climb a tree you planted.” Willow is a “miracle tree”, he declares: fast-growing, home to hundreds of invertebrate species, and free – it grows from cuttings so Powlesland chops off a few young branches and turns them into new trees. Growing beside water, it also doesn’t need watering, handy in this summer’s drought when Powlesland wheelbarrowed water around to sustain other species of newly planted trees. Powlesland works between two and four days in court each week, taking on housing and employment cases to fund his unpaid environmental activism. Clearly, there is a full life’s work restoring the Roding but if he stayed local, he couldn’t champion bigger environmental causes – he co-founded Lawyers for Nature and is also part of the “right to roam” campaign devised by Guy Shrubsole and Nick Hayes. “I’ve come to see the importance of cycling between the micro and the macro,” says Powlesland. “If I just work in Barking it’s irrelevant because these trees will get drowned by climate change. Litter picking is a perfect example. It’s a tsunami of single-use packaging and it feels like trying to wipe off the overflow from the bath rather than turning off the tap, and for packaging we really need to turn off the tap. On the other hand, the local helps keep your sanity and keep you motivated.” For instance, Powlesland deployed his barrister skills in the high court to try to save a black poplar, one of Britain’s rarest native trees, from being chopped down in Wandsworth, south London but his opponents won the case and the tree was removed. “That was very dispiriting. A week later, I had a load of black poplars to plant down here. I dedicated them all to the barrister and the judge whose actions had led to the destruction of the Wandsworth black poplar.” The species may be rare but “Barking now has one of the best collections of black poplars in the country,” grins Powlesland. “There are about 100 of them but no one knows about it yet because they are still saplings, biding their time. We got absolutely no permission from anyone. The council don’t even know. The first thing they’ll know about it is when Barking is transformed – ‘Where do all these massive trees come from?’” Won’t some jobsworth order them to be removed? “To be fair,” he says, “Barking and Dagenham council have been very supportive of the River Roding Trust and gave us some money to plant trees as well.” Our stroll continues along an unofficial riverside path, cut by Powlesland. The trust has received £50,000 of funding to make this an official path but Redbridge council, which owns this section, is stalling on giving it the go-ahead. Opening up this precious urban green space to people is crucial to revive the river, argues Powlesland. The closed riverbank is currently filled with harrowing, rubbish-strewn camps left by homeless people. “People don’t have the headspace to think about nature’s needs and nature gets trashed. This area is really lacking in nature and green space. Why isn’t this a respected, looked-after park? We will build the benches, we will look after it.” At our walk’s end, we reach the Alders Brook, a lost tributary of the Roding where Powlesland is documenting illegal sewage discharges. Thames Water acknowledges that there is a problem in its sewage system but told Powlesland this tiny, inaccessible stream was too difficult to monitor. So he cut another unofficial path and monitors it himself. “One of the richest companies in the country can’t or won’t do it, and no one in authority says to them: ‘You’re not a criminal gang; if there’s a risk of you committing a repeated criminal offence, at least check it’s not routinely happening.’” A Thames Water spokesperson says blockages in the area’s complex and old “foul” sewage system is causing sewage to “cross over” into the surface network. “Thames Water’s engineering department is currently designing a solution that will make an alteration to the network at the point of discharge and divert polluted surface flows into the foul system. This will prevent blockages in future causing pollution to the Alders Brook, while still retaining hydraulic capacity of the network to absorb surface water and prevent homes flooding.” For Powlesland, one way to stop the trashing of Britain’s rivers is the burgeoning rights for nature movement. Giving rivers a legal right to flourish is an idea taking root in countries where indigenous people have pushed legal systems into recognising some “natural” rights, but Britain seems far behind. Nevertheless, Powlesland says people can assert rights for nature simply through practical action. “The RRT and local people are already upholding the rights of the Roding. I relate to the river as a sacred entity, and I’m doing whatever I can to uphold those rights, through law, campaigning or direct action. It comes from the wellspring of the belief that the Roding is sacred, it is a being and it does have rights, and I will manifest those in whatever way I can.” The joy of becoming a nature guardian, he says, is that “anyone can step into it. We don’t need to wait for someone else to change the law. You can connect with your river, form a relationship with it, and then act to uphold its rights. It’s going to be tough. The current legal framework is not conducive to nature protection but it’s better to have people on the ground connecting with rivers than passing a fancy law which no one is going to uphold.” And nature guardianship is not just a duty. “We know nature benefits from it but the more you put into a place, the deeper a relationship you build, the more you grow to love it and the more you get out of it.” For all the painful reality of saving an abused river, this struggle brings Powlesland great joy, too: discovering sand martins from sub-Saharan Africa nesting in old drainage pipes at the river edge, watching kingfishers flash past in their hunt for fish, savouring the fruiting of apple and peach trees inadvertently planted by motorists hurling cores from their cars on the North Circular; all the amazing signs of the natural world’s indefatigable lust for life that matches his own.