Ban on unloading of Polish coal at a Thames wharf . The Polish coal brought to the Thames in the Norwegian ship Lysaker III for Messrs . Bowater ' s Paper Mills , Ltd . , was not allowed to be unloaded at the firm ' s Northfleet wharf . Permission was refused by the customs authorities on the ground that the wharf was not a proper wharf for the unloading of foreign coal . Photo shows , the coal ship Lysaker III at Gravesend . 18 January 1934