Groves joined the
King's Shropshire Light Infantry where he was commissioned a
second lieutenant on 18 October 1899. He served with the 2nd battalion of his regiment in the
Second Boer War, The war in South Africa ended in May 1902, and he returned home later that year, on the in December 1902. He was employed with the West African Regiment (1903–04) and was Territorial Adjutant (1909–12). In 1914 he joined the
Royal Flying Corps, serving with Air Services France (1914–15). On 29 April 1915, he received his Royal Aero Club Aviator's Certificate passing on a
Maurice Farman Biplane at Farman Aerodrome,
Étampes. He did much active flying in the
Dardanelles (1915–16). Between 1916 and 1918, he was Chief of Staff,
Royal Flying Corps, in the Middle East "which then embraced four theatres of war". In 1918 he was made Director of Flying Operations at the
Air Ministry. He was then Britain's Air Ministry Representative at the
Paris Peace Conference (1919) and British air adviser to the Supreme Council and the
Conference of Ambassadors (1921–22). Groves retired from active service in 1922 with the rank of brigadier general. Based on his experiences on active service, Groves realised that Britain needed to radically rethink its approach to air strategy. Shortly after his retirement from the forces, he proceeded to campaign "for the creation of an effective striking force and for a proper regard for the patent realities of civil aviation". His opinions attracted the interest of
Viscount Northcliffe and in 1922 a series of articles on "Our Future in the Air" were published in
The Times. He remained a forceful campaigner for an immediate expansion of the RAF to parity with the largest European force within striking distance. In 1939 Groves returned to active service being made Deputy Director of Intelligence at the
Air Ministry with the rank of
air commodore, a position he held until April 1940. He was then seconded to the Foreign Office before being demobilised in 1946. ==Military strategist==