Can wild brown trout really be caught amongst the urban decay of south London? Some online detective work and Google Maps Satellite View had located a spot I wanted to try. The renewal of the River Wandle – from open sewer to trout stream – is well documented elsewhere on the web, and it is nothing short of remarkable that such clean water could be found in London.

I half-expected this trip to be just a reconnaissance without getting a line wet, but my initial peek over a bridge showed a big trout in unbelievably clear water. I ran back to my vehicle and tackled up: Fly Rod, Floating Line and size 12 GRHE.

This section of the river may look idyllic in the photos, but this was fishing at its most urban. Dumped wardrobes and other debris decorated the water. This stretch ran alongside an abandoned council estate.  It was starting to feel like the zombie film “28 Days Later”.

Again, I fear my lack of stealthy approach to a river has let me down. Too splashy and too close to the fish; additionally I was silhouetted against the sky. The trout must have been spooked and disappeared. Gin-clear water revealed every inch of the river bed; I could see they were gone.

As I stared forlornly under the bridge at the trout that were no longer there, three lads with a spinning rod asked if I’d seen any fish. Their accents put me in mind of Brad Pitt’s infamous role as bare-knuckle boxing Irish Traveller Mickey O’Neil. “28 Days Later” was turning into Guy Ritchie’s “Snatch”.

The lads promised to show me a “hole” that was full of big trout. Further along the river they indicated the unlikely spot. This unpromising looking pool did indeed hold a number of trout. My new-found companions tried to snag a trout with a spinner, and I made the best casts I could in the tight space.  The fast flow of the stream, and tight angles meant I couldn’t quite get the fly where I wanted.

The ginger-haired one asked if he could try out my fly rod. I was hesitant, but let him have a go. Was this going to end badly? He surprised me by demonstrating a casting technique he’d learned in Scotland. His trick was to make a ‘wave’ in the line vertically above the water, then flick it into the required spot. I was genuinely impressed.

I thought to try out a dry fly, but found out to my cost that the 5X Fluorocarbon tippet (0.165mm ) was too thick to thread through the eyes of my size 12-16 dry flies. A Diawl Bach was substituted. A few more flicks into the pool as the light was fading still couldn’t connect.  Retracing my steps, I took one last look at the site where I first detected the trout, but saw no fish. At 9:30 p.m. it was getting too dark to see into the water. I gave up for today, but am wanting to return.

The Wandle Trout remain elusive.