Britain and Argentina clashed at the International Tribunal for the Law of the Sea (ITLOS) in Hamburg this week over the Sea Lion offshore oil project near the Falkland Islands, with Argentina asking the tribunal to order drilling suspended and Britain warning that a halt would devastate the islanders' economic future. The two-day hearing on Argentina's request for provisional measures opened on Tuesday, November 10, and continued with a second round of arguments on Wednesday, November 11.

Source: The Guardian

Argentina argues that the project breaches a 1976 UN resolution calling on both countries to avoid unilateral action while their sovereignty dispute over the islands — known in Argentina as the Malvinas — remains unresolved, and that it poses environmental risks. Argentina's chief foreign ministry legal adviser, Mario Oyarzábal, disputed the islanders' right to decide the ownership of the resources in the surrounding waters and said Argentina was prepared to negotiate all aspects of the dispute. He also argued that Argentina would bear the consequences of any oil spill; UK lawyers responded that the risk was low and that the companies involved had taken steps to mitigate it.

Ellie Reeves, representing the British government, argued that Argentina was using the proceedings to advance its claim to the South Atlantic islands, that the tribunal had no role in deciding sovereignty, and that islanders had a right to develop their natural resources. “The measures sought would have devastating consequences for the Falklands people,” Reeves told the tribunal, warning that suspending drilling would kill the project. Asked whether Britain would comply with the tribunal's ruling, she said she respected the institution but would not anticipate its decisions.

What is the Sea Lion project?

Sea Lion sits in the North Falkland Basin, roughly 200 kilometres (about 107 nautical miles) north of the islands, in an area of about 541 square kilometres. It is led by Israeli company Navitas Petroleum, which holds a 65 percent interest, with British partner Rockhopper Exploration holding the remaining 35 percent. The partners took their final investment decision in December 2025; drilling is scheduled to begin in March 2027, with oil production expected from 2028 and continuing for about 35 years. The project is estimated to be capable of roughly tripling income per head for the islands' roughly 3,400 residents, who currently depend heavily on fisheries.

Argentina lodged its request for provisional measures on October 13 under the UN Convention on the Law of the Sea, asking the tribunal to order the UK to halt the authorised activity while a fuller arbitration proceeds. Buenos Aires has also moved at home: in September an Argentine federal court ordered the project suspended, and the foreign ministry filed a criminal complaint against companies involved under a 2011 law barring unauthorised hydrocarbon activity on what Argentina considers its continental shelf. The UK rejects Argentina's position and maintains that activity licensed by the Falkland Islands Government is lawful.

No ruling was reported by the end of the hearing. Rockhopper has said a decision on provisional measures is expected before the end of 2026. The case revives, in a courtroom, the sovereignty dispute that led to the 1982 Falklands war: Britain administers the islands, whose residents voted overwhelmingly in a 2013 referendum to remain a British overseas territory, while Argentina continues to claim sovereignty and presses its case through international forums.