The British government’s plan to “take back control” of its waters after leaving the EU is about to be challenged by a claim from Denmark that its fishermen have a historical right to access to the seas around Britain dating back to the 1400s.
Officials in Copenhagen have mined the archives to build a legal case that could potentially be fought in the international court of justice in The Hague, although officials hasten to say that this is not their intention.
Denmark is seeking a Brexit deal that recognises the right of its fleet to continue to exploit a hundred shared stocks of species such as cod, herring, mackerel, plaice and sand eel.
Officials say 40% of Danish fishermen’s annual take is from waters within the 200-nautical mile exclusive economic zone around Britain, over which the UK may seek to impose greater control when it leaves the EU. Some of Denmark’s coastal communities are almost entirely economically dependent on access to UK waters.
The development suggests that leaving the EU will not reap the dividends promised by prominent leave campaigners, including the foreign secretary, Boris Johnson, who has claimed that the union’s “crazy” common fisheries policy has halved UK employment in the industry.
The Danish position is likely to be mirrored by the seven other member states who will be affected if the UK seeks to limit access to its waters to EU fleets after 2019, it is understood.
Denmark’s foreign affairs minister, Anders Samuelsen, told the Guardian the issue was crucial to many communities in Denmark and that they would be making their case through the EU’s chief negotiator, Michel Barnier.
“Danish fishermen have historically been fishing across the North Sea. The common fisheries policy in the EU has regulated this, based on historical rights and preserving our common stocks that don’t follow economic zones,” he said.
“Clearly, this is very important for many fishing communities especially along the Jutland coast, and we all put our full support behind the EU’s negotiators to find the best way forward.”
The issue took on added urgency for Europe’s fishing communities last October, when the UK’s fisheries minister, George Eustice, promised British fishermen, who have long claimed to have suffered under the EU’s common fisheries policy, hundreds of thousands tonnes of more fish when the UK leaves the union.
About a third of the catch of all European fishing fleets is from British waters. The industry estimates that a loss of access would lead to a reduction of about 50% in European fleets’ net profit and the loss of 6,000 full-time jobs.
Copenhagen plans to point to the UN convention on the law of the sea, which instructs states to respect the “traditional fishing rights” of adjacent countries within sovereign waters. The UK and Denmark are both signatories.
The so-called London convention on fisheries, which European states including the UK and Denmark signed in 1964, also recognises historical rights of access to the waters of the UK.
The Danish government also believes the quota system in the common fisheries policy provides evidence of historical rights, given they are based on traditional fishing patterns.
Niels Wichmann, the chief executive of the Danish fishermen’s association, which holds a place on the Danish ministry of food’s Brexit taskforce, said: “We have a common sea basin where we can fish. We have always had that.
“The British claim of getting back your waters is a nonsense, because you never had them. Maybe for oil or gas but not for fish.”
Wichmann also said the EU should threaten to block the sale of British fish on the continent unless the UK sticks to the status quo on access and quota shares, a position shared by the European parliament’s fisheries committee.
The Danish MEP Ole Christensen, who sits on the committee, said: “If, and I am really not hoping for this, UK and EU27 does not reach an agreement, it would be terrible for both parties.
“If we are not able to fish in UK waters and the UK cannot export their catch to the EU27, it will hurt everyone, not least the people who make their living in the sector. For the sake of everyone, we need to keep an open mind and work on getting a fair deal.”
Only around 11,000 people are directly employed in fishing in the UK, but Britain’s trawlermen were among the most vocal critics of the EU during the referendum, fuelled by frustration over controls on fishing quotas, which have been blamed on Brussels.
A flotilla on the Thames, led by Nigel Farage, proved to be one of more memorable moments of the referendum campaign.