Iam a fly-fisherman. Okay, there, I have said it. Do not think this means that I go to the Blackfoot river with Brad Pitt and shadow- cast my flies over waiting trout that leap out of sparkling streams to take my fly in a whirling colour of motion.

Oh, no. I am the guy whose flies get hooked on the trees, caught on the bottom of the river or end up embedded in my hat (or, on a few occasions, in the back of my hand). The rivers I fish are all too high or too low, too clear or too muddy. I have spent the budget of a small country on fly-fishing equipment.

If you piled up all of the currency that I have burned in spending on transport and accommodation, you could light a fire from green wood. My fishing companions are often clowns. On rivers, either they stride through my allocated stretch of fishing waters, having strode through their own, or they hang just behind me, silently urging me to fish faster so that I will allow them to get to the next beat.

Sometimes it is not trout I am after but tiger fish. For this, I go to the Zambezi river. In years past, I used to go with a group and take potluck regarding who I fished with. More clowns – like the man who, for five days, told our guide where to fish. Our guide, who had guided the Zambizi for 11 years, up and down the Kusai channel, just sat patiently and did as directed. Then there was the man who was ‘up an at ‘em’. We had to be on the water, with a cold breakfast, by 06:30. Fish until 13:00. Lunch and then back again, in the hot Zambian sun, from 14:00 to 18:00. I saw no evidence that we caught more fish than anybody else.

And there was the man who, the moment I caught a fish, would cast onto the spot from whence it came. Thus, while fishing, I work out the mathematics of fly-fishing. It is not too complex: you have to be at the right place, at the right time, with the right fishing flies and the right water temperature.

Not too difficult, huh? In fact, this means that you have a chance of 1 in 24 of catching a fish. If you fish for eight hours a day, for five days, the odds become a bit better – about one in three.

There are other odds which you do not know about, secret odds: if you join a group of people who are going on an organised fishing trip, ask yourself: “Why are we going at this time of the year?” The answer is that it is the time of the year that the fishing is poor and the fishing lodge owner cannot fill up the accommodation. Thus, he offers a discount to fishing tour operators to rope in the bumblers (as I am) to go to fish the mighty waters.

Who cares if they catch fish or not. If you ask the guide what the best time to fish is, he will say: “All the time, suh”. I can promise you it is the same answer, from the Okavango to the Chobe. It must be part of the approved guide training.

Last of all, in the fly-fishing industry, are the fishing writers. These are self-appointed muses whose grasp of English grammar and the ability to tell a storyline hover close to zero. In fishing magazines, they eulogise about trout that they have “snared with a caddis emerger tied with two hackles of a dogs whiskers, fished deep” or “fishing a light drift with a caledon hackle snack I was soon rewarded with a fine 4 lb fish . . .”

Who knows what they mean, but oh! They do seem to make a living out of it. So why, why, why do I fly-fish if it is so irritating? Because, dear friends, when I catch a fish, it really is great . . . and allows me to drudge away in the engineering world, dreaming of other things.