The trial starts on Thursday of a man accused of running the biggest underground banking network ever uncovered in the Netherlands. Thanas B, a 53-year-old Albanian Greek was arrested last year in his Athens headquarters and extradited to the Netherlands.

B allegedly played a pivotal role in a European network of bankers handling money resulting from crime, public prosecutor Peter Huttenhuis told broadcaster NOS. Underground banking systems are essential for criminals who need to access and offload illegal cash, mostly from drug transactions, Huttenhuis said.

It is relatively risk-free because no cash crosses the border. Criminals supply a local banker with money which is then paid out to them by another banker abroad, for instance in payment for a drug delivery.

Contacts with the bankers are organised via so-called money brokers and both are paid commissions by their criminal clients.

Police and the prosecution office have been trying to disrupt the parallel banking system since 2021 making it harder for criminals to move and access the money.

The Dutch part of the operation managed by B involved €1 billion in cash on an annual basis, Huttenhuis said. “That’s a lot of big shopping bags filled with millions that were being driven around every week,” he said.

The arrest and extradition of B is the biggest blow to underground banking in the Netherlands so far. From his base in Athens B allegedly managed couriers who ferried money to and from criminal clients. Most were legally employed handymen, painters or window cleaners without a record who could use their vans for transport unobtrusively.

The money was counted and hidden in two warehouses in Wateringen and Nieuw-Vennep, the prosecutor said.

A number of people who were part of the Dutch network have already been convicted, including a money broker who was sentenced to seven years in jail. The couriers were given between one and four years in 2023.

The public prosecution office said it is not clear to what extent the arrests have undermined trust in the underground banking system. “We hear that commissions the money brokers are asking from bankers are going up. And we also see that big money transports are more difficult to organise. So we think it is having some effect,” Huttenhuis said.