Sir Winston Churchill World War I, Commem. Cover. The Centenary Cover which was a limited edition of only 100 covers, commemorated the spiriting away of the UKs Naval Fleet from Portland Base to Scapa Flow, in the Orkneys on 28/7/1914. Churchills pragmatic first action of World War I. The cover bears the special Churchill, Royal Mail commemorative, postmarked with Royal Mail Maritime Scapa Flow Orkney illustrated postmark dated 28/7/14.