A frosty start with ice on my local pond demanded a change of venue and I drove to the local river nearby to check on the condition of the water coming over the weir. The river has suffered many minor pollution events recently, but today the river was crystal clear and I unloaded the van to walk to a nearby swim.

On the inside of a bend, the flow passed beneath an overhanging bush and with only a pole with me, set up to trot along the opposite bank into the bush. Due to the bright sunshine, I could see the bottom beneath the bush, which seemed devoid of fish, but the proof would be in the fishing.

Taking out a pole rig with a 4 No 4 ali stemmed stick, I added another four feet of line to avoid the pole top being visible to the fish, as it trotted the float down to the bush. This gave three metres to hand, needing to break the pole from five metres to three. I tried a small ball of liquidised bread upstream of the  bush, watching it break up and drift down in a cloud, before punching out a 6 mm pellet for the size 16 barbless hook. Casting over to the roots opposite, the float had only drifted a foot before it dipped, then slowly sank, as though on the bottom, but a flash of silver when I lifted, then the elastic stretching out of the pole, said that I had hooked a nice roach.

The fish was very cold to the touch on an already cold day and decided against another ball of bread just yet. A couple of smaller chub followed, so chanced another small ball of feed. Back over, the float lifted and sped downstream. I struck and could now see a chub fighting hard toward the roots, pulling the pole round and extending the elastic to bring the pole back to unship the bottom two metres. The chub’s mouth was soon out of the water and heading for the landing net.

Next put in, the elastic zoomed out downstream again, as a larger chub zig-zagged across the bottom, using the length of the pole to steer it away from a sunken branch, before bringing it across to the net.

Dip, dip, sink, strike. A dace was next, these fish only introduced by the Environment Agency a year ago, after oil pollution virtually wiped out the fish stocks. Although a Thames tributary, the river has several weirs between this point and the main river ten miles away, dace never being caught this far up.

This dace was only a few inches last year and has already put on a couple of ounces, a good sign for the future.

The chub kept coming, interspersed by more dace and small roach, feeding a small ball of bread upstream every few fish.

Trotting past a raft of leaves, I expected another small roach, but the elastic came out again with a hard battling chub, that ran upstream for ten yards, before it turned to swim back toward the landing net.

Then the bites dried up, as the river took on a blue tinge. This has happened so many times now, that I feel that the river must get polluted by someone tipping something down the drains a mile upstream into the system. Last time the river turned white and the fish went off the feed.

As if on cue, my phone rang. It was the local Environment Agency officer, who knows that I live in the area. He was asking if I could drive down to look at the river, as they had just had a report of a strange smell coming from the outlet. I replied that I could go one better than that, saying that I was fishing two hundred yards downstream from the outlet, the river has turned blue and the bites have stopped.

Once this happens, it is pointless to continue, the river is dead for at least an hour and if more is dumped, then the day is wasted. I packed up, looking down at my bait tray to count the punches, each one a fish.

I had thrown the small fish straight back, but 90 minutes of actual fishing had seen the start of what could have been a memorable net of fish, releasing these back to the river in the landing net.

By the time that I had loaded my trolley, a Thames Water engineer had arrived and we walked down to see if any other anglers had been affected by the change in colour. There was only one, two hundred yards down from me, saying that his bites had dried up too. The fish are all fat and healthy, but something is ruining the fishing. Walking back to the van, the river had cleared again.