This is the crest of the 'Board of Ordnance Submarine Mining Service'
Engineers had been organised by the Board of Ordnance since 1716, but became a separate corps under the War Office, when the Board was abolished in 1855. The Submarine Mining Service, of the Royal Engineers was formed at Chatham in 1871. The Service installed, maintained and operated underwater defences in the approaches to dockyard ports. The vessels were crewed by uniformed civilians.
Their badge, pattern sealed 25th October 1886 (L of C 5121), was the 1806 crest of the Board of Ordnance arms on a Blue Ensign. The Admiralty took over the Submarine Mining Service in 1904, which by then had 68 vessels and about 130 small craft in harbours throughout the Empire. The War Office retained the badge, which was renamed in the 1907 Admiralty Flag Book as, "War Office : Royal Engineers". However the badge was endorsed as obsolete in 1909 (L of C 14808).
One of their ensigns is preserved in the Royal Engineers Museum, Gillingham, Kent, and another, that of the 48th Submarine Mining Company, Royal Canadian Engineers, in Hood Building at Esquimault, British Columbia.
