Inspectors conducted 46 site visits since the experiment entered its operational phase last April and said there are no indications that any licenced grower has been involved with the illegal circuit.

Almost all the breaches involved either incorrect entries in the mandatory tracking system or failure to meet site security requirements such as perimeter fencing and badge-only staff access.

In total, the inspectors issued 19 informal or formal warnings and four fines, ranging from €1,000 to €20,000.

Under the regulatory framework, every plant carries a unique tracking code allowing cannabis to be traced from cultivation to the coffeeshop counter. Growers must also maintain certified fencing and keycard-controlled entry. The rules apply pharmaceutical-level administrative standards to a product that was illegal just a few years ago.

The inspectorate confirmed there are no signals that licenced growers have had any contact with the illegal circuit, which is precisely what the experiment was designed to prevent.

The “back door” problem that has plagued drug policy for 50 years, where coffeeshops sell legally but buy illegally, has so far remained contained within the 10 participating local authorities.

The scrutiny extends beyond the growers. Coffeeshop inspections rose from eight in 2023 to 145 in 2024, then 375 in 2025, with 56 already carried out in early 2026, the inspectorate said.

The experiment, which runs until 2029, involves 80 coffeeshops across 10 cities including Breda, Groningen and Maastricht. Since April last year all participating outlets have been restricted to legally produced cannabis, in an attempt to finally resolve the “front door, back door” contradiction built into tolerance policy since the 1970s.

Uncertainties around hashish supply remain one of the experiment’s unresolved complications.

Opposition parties including the anti-immigration PVV, the small orthodox Protestant ChristenUnie and the strict Calvinist SGP remain opposed to the experiment.