Three men, aged 50, 53 and 59, have been arrested following a police raid on a secret drugs laboratory in Montfoort, near Utrecht.

The lab had been created in six shipping containers hidden under a mountain of clay used to strengthen dykes, and was invisible from the air and public roads, police said.

Police seized four kilos of crystal meth in the raid, plus 96 litres of raw materials for the production of drugs, as well as a large quantity of waste.

Two vehicles at the premises were also confiscated. The three men have been remanded in custody for 14 days.

Verborgen crystal meth-lab in Montfoort ontmanteld. Montfoort – Op 6 augustus viel de Landelijke Eenheid, onder gezag van het Landelijk Parket,… https://t.co/OLz4nmNnpC #Montfoort via @Politie /

— Landelijk Parket (@landelijkparket) August 7, 2020

Dutch police busted a total of 90 drugs labs last year, a rise of eight on 2018, most of which were in the south and east of the country. Nine of the labs were used to produce highly addictive crystal meth.