Britain's Supreme Court heard an appeal on Tuesday from Nigerian farmers and fishermen seeking to pursue claims against oil major Royal Dutch Shell over spills in the Niger Delta.
The appeal re-opens the possibility of British multinationals being held liable at home for their subsidiaries' actions abroad. It comes after a setback in 2018 when a London court ruled that the claims could not be pursued in England.
A judgement is expected later this year or in early 2021, a court spokeswoman said.
The Ogale and Bille communities allege Shell's oil operations have polluted their land and waters. Leigh Day, the law firm representing the farmers and fishermen, said the communities were seeking justice through British courts because cases heard in Nigeria can take decades to resolve.
The main question for British courts is whether they have jurisdiction over claims against Shell's Nigerian subsidiary, Shell Petroleum Development Company, which is jointly operated with the Nigerian government.
Shell's subsidiary has said "claims by Nigerian communities against a Nigerian company about events in Nigeria should be heard in Nigeria and not the UK".
The Nigerian unit says the spills are chiefly due to oil theft, sabotage and illegal refining.
The Supreme Court ruled last year that Zambian villagers had the right to sue Indian-listed mining company Vedanta in England. The Vedanta decision was frequently cited in Tuesday's hearing, as lawyers for the Nigerian communities and Shell contested whether the cases were similar.
(Reporting by Paul Carsten in Abuja, editing by Ed Osmond and Pravin Char)
