SCOTTISH drug dealers say their profits on cannabis are falling thanks to mass production north of the border.

Gangsters interviewed by academics for ground-breaking new research have complained the market for the Class B substance is “now saturated”.

Their warning of both lower prices and lower margins for cannabis comes as pressure for the UK to follow Canada and legalise the drug.

This weekend a chief constable in England, Mike Barton of Durham, called for “grown-up debate” saying illegal cannabis was putting millions in to the pockets of organised criminals.

The feedback from Scottish dealers was revealed in a new paper by researchers from the University of the West of Scotland, the University of West London and the Metropolitan State University in Minnesota.

The researchers, led by James Densley of Minnesota, spoke to current and former highlevel organised criminals in a major study of Scotland’s increasingly globalised drugs market.

Writing in the International Journal of Drug Policy, they said that their gangland sources “continuously stated that the cannabis market was now saturated, with competition benefitting consumers but eating away at margins for suppliers.”

They added: “The time and specialist skills required to successfully differentiate one’s brand in the marketplace made cannabis growing less attractive for many.”

Most cannabis sold in Scotland is locally produced, often by east Asian crime groups using Vietnamese labour sometimes working in slave conditions.

READ MORE: 'County lines' dealing comes to Scotland

This cannabis has been compared with a cheap superlager

, squeezing out higher quality imported resin.

The new report from the university academics came as the figures from Scottish Drug Misuse Database suggest lower prices and higher availability for cocaine.

Some 11,721 individuals came forward seeking help and were given an assessment, the latest report for 2016-2017 showed. Of these, 19 per cent had used cocaine.

HeraldScotland:

The report said: "For a number of years (2009/10-2014/15), the percentage of individuals reporting recent cocaine/crack cocaine use ranged from 11 per cent  to 13 per cent.

"However, recent cocaine/crack cocaine use has increased to 19 per cent(2016/17) over the last two years, similar to the percentage reported in the pre-2009/10 period. This change may be related to decreases in price and increases in purity of cocaine."

That report, meanwhile, echoed other evidence suggesting the average age of drug users was rising. More than half of addicts who were assessed in 2016/17 were aged 35 or over, up from 29 per cent in 2006/07.

Over the same period the proportion of users who were aged under 25 fell from 26 per cent to 14 per cent.