Reuters is reporting that a legal action taken against Greenpeace by oil major Shell, following the activist group’s occupation of one of the company’s floating oil platforms earlier this year, could be one of the biggest legal throats the group has ever faced in its history.

The news agency reported that according to relevant documents, Shell has filed a lawsuit in London’s High Court for $2.1 million in damages. The lawsuit is also seeking an injunction which would forbid all protests by the group at any of the firm’s infrastructure, at sea or in port at any location in the world, on penalty of Shell making additional claims of up to $8.6 million.

Reuters confirmed the lawsuit with Shell, which noted that the lawsuit was in response to Greenpeace boarding a moving vessel at sea, which was “unlawful and extremely dangerous.”

The company’s spokesperson said, “The right to protest is fundamental and we respect it absolutely. But it must be done safely and lawfully.”

In response, Greenpeace has said that it will accept Shell’s offer of reducing the level of damages it is seeking, if Shell will comply with the ruling of a Dutch court on 2021 which required the oil major to cut its emissions by 45% by 2030. That ruling is presently being appealed by Shell.

The lawsuit relates to an incident in January, when four Greenpeace protestors boarded a moving oil platform belonging to Shell just north of the Canary Islands, as it was being transported to the Shetland Islands. The activists remained on board the platform, displaying signs which demanded the company “Stop drilling, start paying,” until the platform reached a Norwegian port.