Flanders and the Netherlands (under then prime minister Jan Peter Balkenende) signed a series of treaties in 2005 under which the Scheldt would be dredged at 12 critical points to allow large ships to access the Port of Antwerp. Since most of the Westerschelde, as the channel is known, is in Dutch waters between Zeeuws-Vlaanderen and Walcheren island in Zeeland province, the work had to be carried out by the Dutch.

The first problems surfaced in 2009, when, in response to what was seen as foot-dragging by the Dutch government, Open VLD member Annick De Ridder called for a boycott of Dutch mussels and oysters.

The dredging has since been carried out, but the latest problem surrounds one of the other measures in the treaty. That measure calls for the Hedwigpolder, a stretch of land below sea level along the coast of the Westerschelde near the entrance to Antwerp harbour, to be surrendered to the water so that it can become a breeding place for water birds and a site for the growing of the typical water plants of the estuary. This is to be done in compensation for existing estuary marshes that will be flooded as a result of the dredging.

Instead, the Dutch government announced last week it had decided to flood two different polders, close to Vlissingen at the other side of the Westerschelde. The consequences for Flanders, the government calculated, will be a cost of about €250,000. “The Dutch government has shown itself to be untrustworthy in this matter,” Antwerp’s alderman for the port, Marc Van Peel, said.