Despite efforts to clamp down on marijuana plantations, growers in the southern province of Limburg turn over some €240m a year, according to calculations by local paper De Limburger.

Last year the police dismantled 599 plantations in the province. Using the police estimate of finding one in three, this would mean there are 1,800 plantations in the province.

Based on an average of 280 plants and five harvests of 30.9 grammes a plant, this would give production of over 72,300 kilos, the paper calculates. According to justice ministry figures, coffee shops pay an average of €3,280 per kilo. This would bring turnover to €237m.

The paper says this is in sharp contrast to the number of suspects who end up in jail.

Of the 343 people who appeared in court on charges of marijuana production, two-thirds were given a suspended sentence, a fine or community service.

The paper says the public prosecution department supports its calculations.