Dr. Martina Lawless:

There is limited evidence that free ports do much to improve overall trade. Largely, they move trade to the location of the free port, where goods can come in, not have to pay further tariffs, and be further processed by firms in the region and re-exported. For firms in that area, there is a potential benefit, given that they can take in their goods tariff free and re-export them without having to deal with tariffs. That requires, however, an extreme level of checks around the free port to ensure that the goods being unloaded and processed tariff free within the location will not enter general circulation or be sold to firms not in the region. The benefit is very much a distributional issue to firms within the location but it comes with a significant cost for the checks required to keep the free port activity separate from the rest.

Moreover, free ports are allowed in the EU and the policy could have been applied in any event. Rotterdam is a free port, where goods come in and are reprocessed, put on separate ships and moved on-----