By Clotaire Achi and Pascal Rossignol
Boulogne-sur-Mer, France (Reuters) - French trawlermen angered by the slow issuance of licenses to fish inside British waters after Brexit on Thursday blocked lorries carrying UK-landed fish as they arrived in Boulogne-sur-Mer, Europe's largest seafood processing centre.
Britain's post-Brexit trade deal with the European Union allowed the bloc's fishermen to keep fishing deep into British waters, but only once they had received a license.
Those licenses were expected to be issued swiftly but instead some 80% of the French fleet in the northern Hauts-de-France region, from whose coastline Britain's southern shores are visible, were still waiting, French fishermen said.
"We thought it would be a matter of days. Four months on we've barely moved forwards," said Bruno Margolle, who heads the main fishermen's cooperative in Boulogne-sur-Mer.
Some 80 fishermen set off flares on the Boulogne docks, blocked two trucks with a barricade of wood pallets and barrels, and put up a sign that read: "You want to keep your waters??? OK ... So, keep your fish!!!".
Many of the skippers struggling to obtain a license were unable to meet the British demand for electronic data showing they had fished in UK waters during the five years running up to Britain's 2016 referendum on EU membership, Margolle said.
Britain maintained an evidence-based approach to licensing EU vessels using information supplied by the European Commission, the British government's Department for Environment, Food and Rural Affairs (DEFRA) said.
"(We) consider this reaction to be unjustified," a DEFRA spokesman said. The British government had raised its concerns over the protest with French authorities, the spokesman added.
The French government late on Thursday urged the European Commission to take "firm and determined action" to ensure Britain applies the deal.
"We will act in a spirit of European solidarity and cooperation with Britain, but the urgency of the situation compels us all to speed up efforts," Europe Minister Clement Beaune and Sea Minister Annick Girardin said in a statement.
About two-thirds of UK-landed fish are exported to the continent. In the first weeks of the year, Britain's exit from the EU's orbit led to a chaotic breakdown in supply chains, which used to see Scottish scallops and langoustine in French shops barely a day after they were harvested.
Meanwhile, fishermen in northern France say their livelihoods depend on access to British waters, where they chase mackerel, whiting, squid and other species.
Margolle said French fish stocks risked being depleted if French fishermen could not cross into British waters. Some fishermen were keeping their boats tied up in port, he said.
"It's not worth going out to sea to lose money," Margolle said.