THEY are Scotland's cannabis connoisseurs, the nation's self-styled "ganja gourmets" – and they are driving up the cost of the nation's most widely used illegal drug.

Soaring demand for increasingly sophisticated varieties of cannabis –the weed equivalent of a fine Barolo, Sancerre or Chateauneuf-du-Pape –has doubled the average price in the last year alone, the Sunday Herald can reveal.

One gramme of the drug now costs an average of about £10, the same price as a bottle of decent wine.

Kenny Simpson, a veteran detective of three decades now acting as a civilian expert for the Scottish Crime and Drug Enforcement Agency (SCDEA), explained: “A more discerning market is developing. We are seeing a lot of people getting involved in home-grown cannabis.

“We have a growing cottage industry because of the money to be made, because the price of cannabis – the flowering tops, the buds – has doubled. But the quality of the product has also improved greatly. People used to just talk about ‘cannabis’. “But now we are seeing varieties such as ‘AK-47’, ‘Purple Haze’ and, especially, ‘Cheese’.”

“Cheese” might sound like a bad version of a Chris Morris parody on The Day Today, but there is big money to be made in this cottage industry for high-quality skunk.

A single gramme of marijuana sells, on average, for £10, Simpson said. Its resin is cheaper, at £5 per gramme, but that is up from £2.80 this time last year.

The Sunday Herald was this week cited prices slightly lower than these, £25 for one-eighth of an ounce, the standard measure for the product, roughly 3.5 grammes.

Cannabis resin, or hashish – now often a far cry from the poor quality “nine bar” or “soap bar” product of recent years, can also command huge prices.

Simpson reckons the resin market is also getting increasingly sophisticated, especially for those who refer to “first presses” of hashish, as if they were buying virgin olive oil in a delicatessen.

Police use the annual T in the Park music festival at Balado in Kinross as a kind of barometer of the Scottish drugs scene.

Simpson said: “At this year’s T in the Park, I saw a real change from nine bars – you know, the soap bars, which are still quite common – compared with last year’s. We are seeing more and more cannabis coming in from Afghanistan, good-quality, oily resin.

“They produce cannabis resin in three or four stages.

“The first yield is the really good-quality stuff. They go through the process again to get the second batch. The fourth stage is used for making the nine bar, that is the poor cousin. We are seeing a more discerning resin market too.”

Interestingly, law enforcement sources are far from convinced that the more expensive strains are necessarily stronger than the cheaper ones.

However, some – popularly but not always accurately branded “skunk” – can have up to 10 times as much tetrahydrocannabinol (THC), the active component of cannabis, as the grass smoked as recently as a decade ago.

It is the THC that can – especially for a user with a predisposition –spark serious psychiatric and other health problems.

So why is the trade going upmarket? Were there not always puff-buffs, discerning smokers who appreciated varieties in much the same way as wine-lovers or whisky bores?

“The old stoners, of course, knew their stuff,” says Simpson. “I have known a few over the years. But then you also had the bottom of the market, your Buckfast drinkers, those who will use anything.”

However, some at the low end of the market did develop an interest in grass, rather than resin.

Triads, Chinese organised crime groups – often using what amounted to Vietnamese slave labour, moved heavily in to Scotland over the past five years or so.

They built huge commercial cultivations, hidden in private homes, producing so much of the all-important cannabis buds (often, though, connoisseurs argue, tasteless ones) that Scotland, for the first time, became an exporter of the drug.

But then Operation League, involving every force in Scotland, including Simpson’s SCDEA, and other bodies such as landlord groups and power companies, was set up, the Asian gangs took a hammering and scores of drug factories were shut down.

That operation hit supply – and is continuing to do so. It also hurt the gangs behind it.

Simpson said: “Cultivations continue to be detected, but they are far fewer in number, and the SCDEA, in collaboration with other forces, has caused considerable disruption in terms of recoveries, arrests and convictions. Scotland is now a hostile environment for this type of organised criminal activity. This is a real success story.

“As a consequence of disrupting commercial cultivations of the drug, more people are choosing to grow their own. Commercial cultivations are very difficult to keep concealed and we are still in the business of detecting them.

“Cannabis is a class-B controlled substance.

“We have not taken our eye off the ball at all. We are as interested in cannabis as we are in any other substance. The price is going up because the product is better and the organised crime gangs are having to work harder to source it.

“If you go back five years and you bought an eighth of cannabis, you would be guaranteed to get stock leaf and buds, a mixture of the good and the bad of the plant. Now, when cannabis is sold, there is a tendency, even if they are using the leaves, that they will disguise them, shred them down.

“The way they market their product and the way they sell it is ‘Here you are, this is good quality!’. It is like every other business: if you are selling a substandard product, people will go elsewhere.”