British explorer, an officer in the Indian Army who later joined the political service (1905) and was assigned political officer for Sikkim and Bhutan (1921-1928). He was also a keen amateur naturalist who collected lepidoptera and phanerogams on his expeditions to Tibet, Nepal and China, for example as a member of the F.E. Younghusband military expedition to Lahsa (1903-1904). The Anglo-Tibetan Convention resulting from that expedition was subsequently repudiated by the British government following protests from Russia, Germany, the United States, France and Italy.

Bailey travelled overland from Beijing to Assam while on leave (1911), but was stopped in Tibet. He secretly returned to Tibet (1913) and explored the Tsangpo river with fellow officer Henry Morshead, for which he was awarded gold medals by both the Royal Geographical Society and the Royal Scottish Geographical Society.

Bailey served in the First World War (1914-1915) and was wounded both at Ypres and Gallipoli. He was appointed to the British Mission to Russian Turkestan (1918-1920), British Minister to the Court of Nepal (1935-1938) and Kings Messenger (1942-1943). A commemorative plaque is in Wiveton church, near Cley-Next-Sea in Norfolk. Bailey's plant collecting diaries are in the library of The Natural History Museum and most of his original collections are at BM. Some of the specimens are attributed to 'Bailey's Collector', referring to one or more unnamed local collectors who are not individually credited.