The raid was part of an ongoing investigation by the Central Office for Combating Cyber Crime (CBZC) into the sale and purchase over internet forums of illegal substances and drugs.

The seizure, according to a CBZC statement, is the largest by a cyber-crimes unit in Europe.

The 1,770 kilograms of narcotics and psychotic substances were found during a police raid on a house in the central town of Konin along with two production lines and about €90,000 in cash.

According to the CBZC statement, the production lines were capable of producing 700 kilograms of drugs a week.

Two men, aged 52 and 29 and without criminal records, were arrested.

The raid took place at the end of June but the details of it have only just been released.