Drugs gangs continue to find new ways to hide their illegal marijuana plantations from the outside world and the number of plantation busts last year fell 22%, news agency ANP said.

Last year, police and officials from the electricity grid group Stedin found just under 1,000 plantations in private homes and commercial buildings – down a fifth on the year before.

‘Organised crime is becoming increasingly innovative in hiding plantations,’ Stedin’s fraud chief Barthjeu Ammerlaan told the news agency. In particular, cellars with hidden ventilation systems are becoming popular, he said.

Last October the Dutch government said it is to run trials of licenced marijuana cultivation in an effort to take the drug out of the criminal circuit.