GLASGOW'S illegal drugs of choice, and the routes used to smuggle them into the city, are revealed today.

And the results will be a surprise to many.

Detective Sergeant Michael Miller, is part of the Statement of Opinion (STOP) Unit, soon to be renamed the Drug Expert Witness Unit.

The division was formerly part of the Strathclyde Police drugs squad.

Mr Miller said: "There are very obvious trends with controlled drugs.

"The most important thing about drug dealing and the drug market is it's a business - it's there to make money.

"Any effective business wants to sell a product that's good enough to take but is as cheap as they can get.

"For example, cocaine is adulterated a lot to bulk it out and maximise profit. This will happen a number of times all the way down to the end user on the street.

"The purity of cocaine at the moment is about 10%.

"A few years ago it was very, very low. We were seeing 5% but often it would be down at 1%. Purity levels have crept up over the last two and a half years.

"Cannabis resin has become less and less popular. Herbal cannabis or grass has overtaken it.

"Heroin will have its peaks and troughs, like any business it's based on supply and demand. Heroin will fluctuate in price... but it's there and always will be.

"Diazepam is a problem. It's a big problem in Glasgow."

A resurgence of ecstasy-type drugs, which have been linked to several deaths recently, is also presenting challenges for officers.

Mr Miller explained: "Ecstasy disappeared completely for a number of years. Things that were being sold as ecstasy tablets weren't.

"In November 2010 we analysed a number of drugs and the precursor chemicals had came back into circulation.

"In the late 80s early 90s it cost £30 a tablet, then they fell off and ultimately were getting sold at £1.50 to £3 per tablet.

"Then all of a sudden they went back up to £15 for a few months and stabilised at £10 and have remained at that."

Mr Miller has also revealed that there are hundreds of supply routes into Scotland.

He said: "Any way that a person can walk into the UK is a way that drugs can get in. That's the truth. No one can say definitively how the drugs get in. If we knew that we'd get them all.

"A lot of drugs are going through Spain, up through Holland and into the UK. Any way that a person can get from A to B is a way that drugs can come in."

New Psychoactive Substances (NPS), or so-called legal highs, are also an increasing problem for police.

On August 22 officers launched an unprecedented crackdown, called Operation Redwall.

Mr Miller, who was involved in the day of action, said: "My first three years in the drugs squad we'd see a new drug maybe every two months. Now it's every week. There are so many they often don't even have names. People know them as legal highs. They're churning these out.

"When I worked in Glasgow city centre there were hotspots where people would deal in controlled drugs. There were certain places where people would congregate and know there would be dealers.

"It's a wee bit more difficult to target when they are online. Then of course we've got the 'dark web', where you can buy and sell drugs.

"But I have to say, Police Scotland are further ahead than most in dealing with this. I don't know if any other UK force has had an operation like Redwall, where we've put considerable time and resources into tackling NPS.

"That really has made a big impact and the results we got from it have been fantastic."

peter.swindon@ eveningtimes.co.uk