I suppose its human nature to assume that the best is yet to come. After almost 40 years of fishing some of the country's finest wild trout fisheries, I've had some phenomenal fishing, and I must admit I wouldn't mind another 40. But the small chironomid in the ointment is that I may have already had my perfect dream day. Twenty-odd years ago my father and I set out from Kirkwall to fish the Swannay loch one foggy morning in May. We had our doubts about the fitness of the weather as the visibility was poor and there was little if any wind. Our expectation of sport was even lower than the air temperature.

As we pushed the boat off the shore I remember thinking, with a tinge of the undying optimism that afflicts all anglers, that the cloud base was lifting and the chill wasn't quite as penetrating as it had been when we left home. In difficult conditions fishermen hold onto and nurture these small silver linings which drop from passing clouds. It was still glassy calm with not a single sign of trout activity disturbing the small amount of water we could see, but that wouldn't stop us betting against the odds.

It may have been the first drift, or perhaps the second, but it was surprisingly early in the day when my floating line went tight in the middle of the retrieve. No visible sign of fish was evident, but I was definitely in! "Fish", I mentioned laconically to my father. "Good one?" he enquired. "Oh I don't know," I rejoined, "pound and a half-ish, maybe." Suddenly the fish was hanging in the air a matter of feet from the boat, "Bloody hell, he's more like three!" Again he exploded skywards, "Or four!" The fly rod was being put through its paces - horizontal as the fish raced around the boat, and vertical as the fish launched itself in gravity defying leaps. For a fish of its remarkable size it was extraordinarily airborne, and this eventually led to its downfall. As I regained line the jumps were taking place ever closer to the boat and suddenly, with a clatter of gill-covers and a spray of water, the fish erupted from under the gunnel of the boat, arced towards me, struck my chest and dropped into the boat. The ensuing chaos of flailing fish, rocking boat and over-the-top human reaction are best left to the imagination.

Shortly after this entertaining interlude we noticed that the air temperature had risen appreciably and that a thin, pearly haze had replaced the fog. Conditions were markedly improved, but we had to wait some time for the next fish which fell to my father as we drifted on to the Heathery Shore. It was obvious right from the start that this fish was big. It gave not an inch and bored deep and powerfully, exhibiting none of the dash and airborne aptitude of its predecessor. My father fought the fish with one hand and prepared his net with the other. I remember thinking that this netting-preparation was optimistic and somewhat previous as the fish gave not the slightest indication of giving up the fight. Dad slipped the net deep into the water as his rod creaked and groaned under the strain of struggle.

Suddenly the rod sprang upright and the landing net handle jerked in his hand. "Good God, its in the net." he exclaimed, and proceeded to pull the writhing, thrashing, bundle into the boat. Upon disentangling the fish it became obvious that it had slipped the hook, and effectively 'gilled' itself in the net. Things were beginning to take on a slightly surreal aspect.

Still, that was two immense fish in the boat, and the weather was continuing to improve. The wind had strengthened slightly, producing a 'corduroy' ripple (a condition I love on Swannay), the cloud ceiling had continued to lift, and it was now as warm as one could expect in early May. Midge were hatching extensively and, at last, fish were rising everywhere. I remember thinking "My God, we're going to fill the boat". Fish were 'dorsaling' all around us but we couldn't tempt a one. Everything was tried, from the sublime to the ridiculous. Eventually, more in hope than expectation, I stuck on a l/s 12 Worm Fly and stripped it past the nose of steady feeder and he hit it with a thump. "Here we go", I thought, "It worked once, it'll work again." But no, it didn't, and we were forced to retire with but the three. Mind you, what a trio they were - the piscine equivalent of Nijinsky weighed 5lb 5ozs, the suicidal one went 4lb 13oz, and the midge feeder went 2" exactly. Three wild browns for 12lb 10 ozs.

The 5.5 still remains my heaviest wild brown, although I have come close to bettering it on a number of occasions - once in South Uist when a fish came to my flies through a Stilligary wave and I almost wet myself, and a couple of times last year, on Lough Sheelin, when my 'record' could have been shattered. There was also the hooked and lost 'submarine' on Loch Leven which turned the boat round, and others during isolated occasions on other Orcadian lochs - but most often on Swannay.

Amongst them being the fish which tried to take my bob fly as it hovered six inches out of the water, and actually slammed into the side of the boat as it missed the fly. I might have done a better job on that one but for the fact that I was watching black-backed gulls mobbing an otter at the time. There was the monster that smashed me to pieces, due to my incredible folly, whilst drifting the Heathery Shore with messrs Gathercole & Irvine. Both of these fish were seen in their entirety, and there were few doubts as to their weight. Unlike its fish, Swannay is not big by UK standards, consisting of 600 acres of peat-stained water, and, as the bulk of the fishing takes place in only two-thirds of its area, it is also not as daunting a prospect to explore as, say, Harray or Stenness. The southern end of the loch below the Muckle Holm tends to see most angling effort, and this region is rich in off-shore shallows, trenches and weed-beds which provide quality habitat for Swannay trout.

It is a rule of thumb that a rough estimate of the depth of a loch can be arrived at by studying the surrounding landscape. In this respect Swannay is misleading, as the land around is relatively high and slopes down quite steeply, but the loch depth averages only 3 metres. The water, as previously mentioned, is peat-stained and can vary from guinness-like in the early season to the colour of a cream sherry in mid-season. Peat-stained water is generally assumed to be acidic but in this case, due to the nature of the geology of the region, the water is alkaline and abounds with crustaceans and molluscs. The principal food item being the ubiquitous shrimp (gammarus sp.), supplemented with caddis (adult & larva), midge and stickleback which the loch produces in extraordinary numbers. Terrestrial flies such as Crane Fly and Cow Dung are very important, and can appear on the water in very large quantities to the delight of the trout and the angler.

Plenty of food grows big fish, and the best conditions in which to find them tend to be those of high, even cloud ceiling, mild temperatures and just enough breeze to hold steady. All my 3lb+ fish from this loch have come in conditions of extremely light wind, and this is unusual, as the rule of thumb for wild browns is "big wave, big fish".

But where this loch really bucks the trend is in the most successful fishing techniques. The extremely high quality of the dry fly fishing on Swannay is a source of continuing surprise to all and sundry. This loch is the only wild brown trout water in the country where I almost invariably rig up for dries as a first resort and only change to wets when convinced I'm on the wrong tack. Normally, it is fair to assume that browns prefer sub-surface offerings as the bulk of their food consists of items which rarely if ever leave an aquatic environment. This is very true of Swannay where the menu is largely shrimp and caddis larvae, and trout with raw, rubbed blisters on their noses caused by rooting about in the stones are the rule rather than a rarity. To catch such a fish on dry fly is confusing, and doubly so when the marrow spoon shows that nothing vaguely resembling an adult insect has been recently ingested. But I am no longer surprised by such an occurrence on Swannay. Dry fly is so effective on this water that I have no compunction in saying that a competent 'dry' man will out-fish a similarly qualified 'wet' man over the course of a whole season. I'll go further - the dries will take not only more, but bigger and better fish, and this will start in April and continue on, unbroken, until the end of September. In a three-foot wave or a mirror-calm, without the slightest sign of natural fly life or feeding fish, dries will regularly out-fish wets.

And God, how I love it! Nothing can be simpler - forget about retrieve rate or density of line, pattern choice and size, just stick on a couple of size 12 dark seal's fur patterns with a turn of hackle at the head, degrease your leader and Gink the flies, cast them a modest distance in front of the drifting boat, and get ready for action. However, should you wish to fish traditional wet patterns, a brief selection would include Zulu, Bibio, Goat's Toe, Claret & Golden Olive Bumbles, Alexandra, Silver Invicta, Palmered Coch, Palmered March Brown, Peacock Palmer, Loch Ordie and, in desperation, a Black Cat's Whisker. Patterns for dries aren't important, but colours definitely are and should include black, claret, fiery brown and hare's ear with masses of loose fibres brushed out and the odd hackle fibre to kick in the ripple.

If you haven't guessed by now, I'll tell you - Swannay is my favourite loch, and I hope to spend a lot more perfect days on it before I hand in my zimmer frame.