As the river deepens, more seawater from the North Sea flows at a faster rate towards Hamburg, bringing sediment that builds up on the riverbed. The Hamburg Port Authority dredges the river to counteract the build up, which cost taxpayers 120 million euros ($125 million) in 2015.

The two projects amount to an expensive redundancy, Siegert said, with the JadeWeserPort costing $1.6 billion and the Elbe project an additional $940 million. "This is the reason for our protest: They decided on the first port, and now they should coordinate traffic, so that the really large ships can go to Wilhelmshaven or, under certain restrictions, to Hamburg."

In total, the continent lost about $850bn between 1970 and 2008, the report said. An estimated $217.7bn was illegally transferred out of Nigeria over that period, while Egypt lost $105.2bn and South Africa more than $81.8bn.

Nigeria’s crude oil exports, mineral production in the Democratic Republic of the Congo and South Africa, and timber sales from Liberia and Mozambique are all sectors where trade mispricing occurs.

The bulk of Africa’s illicit transfers originated from west Africa, where 38% of all funds leaving the continent were generated. Profit-making activities in north Africa accounted for 28% of the flows, while southern Africa, central Africa and eastern Africa each made up about 10%, the report showed.