LEON Kirk was born with gold fever. "It is the DNA," he says. "Growing up the word 'treasure' blew me away. As a kid I was always looking for shiny stones. But once I saw gold everything else disappeared: it is the top of the pyramid."

Despite his early fascination, Kirk, 53, was a late starter in the gold panning world. "I was in my mid-thirties when I took it up," he recalls. "I used to fly as a hobby and had my own microlight aircraft but I got bored and took a break.

"I had always wanted to find gold. I'm self-taught. In the 1990s when I started, there wasn't the kind of information on the internet that there is now.

"There was no one doing courses and very little equipment for sale. I was scrambling about trying to build knowledge. There was only a small group of people who did gold panning. It is a bit of a secret society."

Over the past two decades Kirk, who splits his time between Glasgow and Castle Douglas, has carved himself a reputation as one of Scotland's most prolific gold panning experts.

He teaches gold panning courses privately and on behalf of the Museum of Lead Mining at Wanlockhead in Dumfries and Galloway as well as designing, manufacturing and selling specialist equipment. Next month Kirk will compete at the World Gold Panning Championships 2017 in Moffat.

Away from his all-consuming pastime, his day job is working in maintenance at Strathclyde University's halls of residence in Glasgow. "I'm one of those people who won't stop at climbing a hill: I have got to do Everest," he laughs. "And that is exactly what I did with the hobby."

All through his life he has had a magpie-like fascination for things that sparkle or shine. Dumfries-born Kirk spent almost a decade of his childhood living in Swaziland – where his father worked in the paper industry – and would hunt for gemstones in the southern African rivers.

While gold panning may typically conjure an image of someone standing knee-deep in water with trousers rolled up and holding a bucket, Kirk explains that there are several methods.

"The first, as you've described, is with your wellies on and a gold pan," he says. "The second is where you use a sluice that looks a bit like an old washboard with ribs to catch the gold.

"Next we have what is called 'dredging' which is done underwater and involves sucking up material from the river bed. That is not allowed in the UK, so no one does it."

"Then there is 'sniping' which requires a dry suit, snorkel and being underwater with very minimal equipment. It is a green way of finding gold because all you are doing is moving gravel and hard-packed material along the bottom of the river. You are not blowing up mountains like a gold mine."

Sniping is Kirk's favoured technique. "It is the Jacques Cousteau stuff and purist part of the hobby," he says. "That is what I specialise in and how I built up my collection of gold."

He has favourite Scottish gold panning spots, but is tight-lipped about sharing the exact locations. "I have one place – Leon's secret river – that I've had up my sleeve for years," he says. "Over time, as you get to know friends and build confidence in them, you will share it with them.

"But you have to protect it because, as you can imagine, the word 'gold' sometimes attracts the wrong kind of people. There are those who think they can make a fast buck, but it is not about that for me. It is about the freedom, countryside and getting away from it all."

Kirk chuckles when asked about the perils of shopping trolleys and old bikes. "To find gold, you need to get to the bedrock of the river which is the plate of rock that surrounds the earth," he explains. "A river will wear into that bedrock and you can have gravel that is 50ft deep.

"What you need is a river where you can quite easily get to the bedrock. Those are normally high on mountains, where there is no shopping trolleys and rubbish. All you tend to get is the occasional nail or coin thrown in by a farmer."

The biggest gold nugget Kirk has found weighs 16.5 grammes, with his second largest 15.1g (to put that in context the new pound coin weighs 9.5g). The nuggets are named Pikoe and Pedro respectively after dogs his mother once owned.

"Scottish gold is typically worth four times the current value," he says. "If gold is worth around £25 a gramme then Scottish gold would be £100 a gramme. There is a very small cottage industry out there making jewellery from pure Scottish gold which is rare and special."

Not that Kirk would ever be parted from beloved gold nuggets. "Most people have a small collection of gold they won't let it go," he says. "It becomes too precious to them. They are keen on hanging on to it no matter what they are offered.

"The smaller and finer pieces of gold I do let go. Make it into jewellery. Give it away. Swap it for equipment. You are not as attached to gold dust. But I have my nugget collection and a specimen collection, which is pieces of gold that are still attached to the host rock.

"Gold comes out of quartz. Sometimes you will find it in the river still attached to the quartz. That is a lot rarer than gold itself. If you can imagine a lovely white stone with gold going through it like a marble effect. Under the microscope it looks stunning."

Ownership of gold rights in Scotland can be complicated. There are, however, a couple of areas where the gold can be obtained legally either by permit or by agreement: Kildonan in Sutherland and Wanlockhead.

Kirk regularly teaches gold panning at the latter site and is happy to share his wealth of knowledge. "I run what I call a 'make a gold digger in a day' course," he says. "People can fast track themselves to the kind of information that it took me two or three years to learn."

In 2015, a Canadian tourist on a Wanlockhead course led by Kirk found an 18.1g gold nugget worth an estimated £10,000. The man almost threw the 20-carat piece back into the river after initially misidentifying it due to the slightly discoloured appearance.

Such rookie errors, says Kirk, are thankfully rare among more experienced panners. "Once you have seen gold for that first time, you will pretty much never mistake it after that," he says.

"There can be the odd occasion where it can be more difficult and you think: 'Hmm, I'm not sure that is gold …' but what you do is take it home, look at it under a microscope and play around with it. If you hit it with a hammer and it smashes into a million pieces then it is stone.

"Sometimes you can get little bits of minerals that are fooling you, they look like gold but aren't. Generally speaking, though, 99 per cent of the time you know straightaway. Underwater it is even clearer because it is magnified two-and-a-half times.

"A flake of gold is like someone shining a torch in your eye for that millisecond as it flashes past. There is nothing else like it."

Around 10 years ago, Kirk switched his focus from solely recreational fun to designing, making and selling equipment through his business Gold Panning Supplies UK, and many of his customers will be competing at the World Gold Panning Championships.

Moffat sits on the River Annan but to ensure a level playing field and stop any claims of unfair home advantage, the six-day event will use specially-made panning pools.

In the individual categories, 30 competitors will each receive a bucket of sand and gravel that has been seeded with between five and 12 small flakes of gold. They must then find as many pieces as possible with a three-minute time penalty added for each one missed or lost.

"The event is a knockout-style competition and can be exciting to watch," says Kirk. "It is like bringing the Olympics of gold panning to Scotland."

The World Gold Panning Championships 2017 take place in Moffat from August 7-12. Visit moffatgold2017.com