Britain and the European Union are facing off in court for the first time to settle a conflict over fishing rights after Brexit. The dispute focuses on Britain’s decision to ban fishing for sandeels in its North Sea waters, which the EU claims violates the Trade and Cooperation Agreement (TCA).

A three-person panel at the Permanent Court of Arbitration in The Hague is hearing the case. The panel, consisting of legal experts from France, New Zealand, and South Africa, will spend three days listening to both sides before issuing a ruling by late April.

The British government defends the ban, saying it is based on scientific research that highlights the importance of sandeels to the marine ecosystem. These small fish are a vital food source for larger fish, marine mammals, and seabirds such as puffins. Britain also argues that the ban helps protect the species’ long-term survival.

The EU, however, claims the ban is unfair, excessive, and not backed by the best available science. They argue it unjustly limits EU fishing vessels’ access to UK waters, a right established by the TCA.

If the court rules against Britain and the ban isn’t lifted, the EU could take retaliatory measures. This would create challenges for Prime Minister Keir Starmer’s government, especially as it seeks to improve ties with the EU. Environmentalists and Brexit supporters are likely to pressure the government to stick to the ban, making any compromise difficult.

The case comes at a critical time, as Starmer prepares to meet EU leaders to discuss defense cooperation and other important agreements. The outcome of this court battle will not only affect fishing rights but could also influence the future of UK-EU relations.