A Greenpeace protest on a ship carrying illegally-harvested Brazilian mahogany has landed the environmental group in the dock under an obscure “sailor mongering” law last used 114 years ago.

The case, the first US criminal prosecution for civil disobedience of a group rather than individual members, centres on action by Greenpeace in April 2002, when activists boarded a ship off Miami and unfurled a banner which read: “President Bush: Stop Illegal Logging”.

Six activists spent a weekend in jail following the incident but 15 months later Greenpeace itself finds itself charged under the sailor mongering law, which has been used only twice since being passed in 1872. The law, which forbids boarding a vessel without authorisation, was orginally designed to prevent prostitutes luring sailors off ships.

The group says the court action is revenge over its staunch opposition to many of the US government’s environmental policies. It plans to argue in the week-long trial that its members were highlighting the illegal mahogany trade.