The blockade was rendered less effective because the Axis could get crucial materials from the Soviet Union until June 1941, while harbours in Spain were used to import war materials for Germany.
Blokade tersebut berdampak kurang efektif karena Blok Poros mengambil material-material krusial dari Uni Soviet sampai Juni 1941, sementara pelabuhan-pelabuhan di Spanyol dipakai untuk mengimpor material-material perang bagi Jerman.