Earlier this month I found myself in Surrey preparing a barbel swim on a tributary of the Thames.

It was later in the afternoon that storm clouds began to build and the sky took on a deep, menacing hue that spoke of rain to come. My friends and I are country folk who can read the weather, but even we were surprised at the deluge that was unleashed as the evening approached.

I remember times of monsoon when I was stuck in the Himalayas back in my travelling days and this was vividly reminiscent. For many hours, well into the night, the rain simply teemed down in a tumultuous curtain and even when I awoke very early on Tuesday morning the air was still heavy with outbreaks of soaking showers.

I got to the river to find it much changed. It had risen perhaps five feet in the 15 hours I had been away and as for the colour, it was impossible to distinguish what was water and what was rain-sodden earth. The swim I had pre-baited had all but disappeared, but for half-drowned trees and bushes providing some sort of landmarks. But it was the smell that struck me in the gloom of that dawning morning. Thick. Sweet. Cloying. Sickly. I wandered downstream and found the cause, a culvert gushing with raw sewage that was flooding the bank and staining the river a putrid grey.

I should have taken water samples or photographs or both as evidence - much good that would have done me - but I didn’t. In something approaching a state of shock I left, taking my bait bucket with me. We know that there are thousands of illegal sewage spills every year and that at times one BILLION litres of untreated sewage empties daily into the Thames close to Twickenham.

I had been told on Monday morning that the town’s sewer overflows with regularity by the owner of the river I was hoping to fish, so what I saw should not have come as a surprise. My experience was like witnessing a burglary, a car crash, an assault or something equally dreadful: you know these things happen but unless you work in the emergency services, you don’t expect them to happen to you. But this had happened to me and the smell was in my nostrils, the sight burned into my memory to prove it.

This spring and summer I have travelled much of the country in my work and virtually every river I have visited has been in trouble, has been degraded and abused in one of many differing ways. Top of the disaster list is escaping sewage in one form or another, both human and animal.

Poo is poo, whether it comes from us, from cows, sheep or, increasingly, chickens. Not one of the regulatory authorities appears to have the budget, the manpower or even the will to do much to change this. If a water company or a chicken farmer is, amazingly, prosecuted, the fine is generally so derisory that it is shrugged off. There is barely a day when we do not read about this environmental crime, or see it covered on television or social media and yet government really does seem to do nothing.

We know the prime minister is surrounded by a host of Westminster Greens emanating from his wife outwards, but their preoccupation appears to be with rewilding and bringing back beavers. What I witnessed is much, much more important. I called this column Rivercide for the simple, obvious reason that year on year we are killing the rivers we fundamentally depend upon and despite the clamour from anglers and some environmentalists, the situation goes from bad to terrible with no sign of reverse.

There is some good news as a postscript to this latest trip. On Wednesday, the river had dropped and the colour fined out. By mid-morning the tipping point had been reached when I knew that a barbel could be caught. The swim had been baited. Two large knobs of Spam decorated a size 4 hook. One perfect cast was made. The angler sat back content to do nothing for as long as it might take for a fish to come along, which after the best part of an hour it did. The bite was ferocious, the battle even more so and when the clonking great barbel was finally in the net, the angler nearly collapsed with relief. One day, I promise I’ll show you the photograph!

I mentioned the owner of the river, but I didn’t say what a wonderful man he is. I also mentioned a couple of weeks back that I am involved with the antique tackle experts at Thomas Turner and I am beginning to see why. Michael, my host, is the world’s expert on the history of the London roach pole.

Of course I had heard of Sowerbutts, the leading maker of poles for over a century, and of course I had heard of the great catches of roach made on the Thames and the Lea back in the 19th and earlier 20th century, but my knowledge was veneer thin. Hours spent talking with Michael and handling the old poles themselves changed my mindset completely and forever. I was handling angling history, gorgeous artefacts made by gifted artisans back when Gladstone was in power.

These were the immense cane creations that living, breathing men from the East End had saved up for and cherished and used to catch a lifetime’s haul of silver-sided redfins. I used to teach the social history of the period, but these poles and Michael’s stories behind them took me beneath the skin, to the beating heart of the capital’s roach fishing heyday in the reign of Victoria.

Those very poles had been grasped by hands calloused from work on the docks or in the factories. They had been wielded by anglers sweating in the summer, freezing in the winter and they must have witnessed decades of roaching triumphs and disasters alike.

That’s fishing for you, a sport that has roots going back millennia, but which still flourishes to this day... providing of course, we can finally sort out what to do with our poo.