Colonel M W H (Henry) Day, MA, CEng, MICE, Royal Engineers was a British Army Officer (retired 9 April 1997) [1] who made the first British ascent (second ever ascent) of Annapurna I. [2] [3] In addition to the first British ascent of Annapurna, he was an active member of the Army Mountaineering Association (AMA) and a member of the Alpine Club (UK) contributing to the Alpine Journal. [4] He was an active climber in the Alps and took part in the first winter ascent of the Grands Charmoz with Rob Collister. [5] He was member of the AMA Tirich Mir (1969) expedition, summiting the peak; [6] the AMA Himachal Pradesh (1973) expedition; [7] the 1976 British and Nepalese Army Expedition to Everest. [8] He led a Royal Engineers expedition to Trisul II (1978) [9] and in 1981 a British Army expedition to the Da Xue Shan mountains in Sichuan province, China attempting to climb Jiaz (6,540 m). [10] In 1987 Henry Day led the climbers attempting to climb the virgin east face of Xixabangma (8,027 m), [11] in China, organised by the Scientific Exploration Society with a view to conducting scientific research en route. In 2008 he organised a climbing expedition to the Georgian Caucasus. [12]