The plan of France to capture Sydney. Not all countries could accept the fact that the UK acquired a whole continent and turned it into one huge prison. In 1802, the French invented how to capture Sydney. They believed that they would need only 1,800 soldiers, and that prisoners should be freed so that they could help them cope with the remaining British soldiers. The plan was not implemented, and it is unclear why. Historians say that after the defeat in the Battle of Trafalgar, France no longer had the resources to fight.