Churchill, as First Lord, had direct responsibility for the conduct of naval operations in the Norwegian campaign. Before the German invasion, he had pressed the Cabinet to ignore Norway's neutrality, mine its territorial waters and be prepared to seize Narvik, in both cases to disrupt the export of Swedish iron ore to Germany during winter months, when the Baltic Sea was frozen. He had, however, advised that a major landing in Norway was not realistically within Germany's powers. Apart from the naval success at Narvik, the Norwegian campaign went badly for the British forces, generally because of poor planning and organisation but essentially because military supplies were inadequate and, from 27 April, the Allies were obliged to evacuate.