In 1916, during
World War I, Cazenove passed out of Sandhurst and was
commissioned as a
second lieutenant into the
Coldstream Guards, in which he served on the
Western Front in 1917–18. He was
mentioned in despatches. Cazenove served as the
adjutant of the 2nd Battalion, Coldstream Guards, in 1922–25, and was on the staff of
London District 1926–29. He was promoted to
major in 1933 and held the appointments of
brigade major to the
Brigade of Guards (1933–36) and Officer Commanding Guards Depot (1937). In 1939 he was promoted to
brevet lieutenant colonel and took command of the 1st Battalion, Coldstream Guards. In September 1939, during
World War II, the battalion, part of the
7th Guards Brigade of the
3rd Infantry Division, under
Major-General Bernard Montgomery, was sent to France to join the
British Expeditionary Force (BEF). During the
German invasion of France and Belgium in May 1940, the battalion fought in the
delaying actions along the Ypres-Comines Canal and was then
evacuated from Dunkirk. The 3rd Infantry Division was the first formation of the BEF to be re-equipped to man the defences of
Southeast England. Later that summer (18 August), Cazenove was appointed to command of the 7th Guards Brigade with the rank of temporary
brigadier. On 15 September 1941, his headquarters was redesignated Headquarters
Guards Support Group (a mainly
artillery formation supporting the
Guards Armoured Division) and the 7th Guards Brigade ceased to exist. Cazenove continued in command until 10 October when he could be replaced by an artillery officer. Cazenove was next appointed commander of the
73rd Independent Infantry Brigade from 10 October, and commander of Cornwall Coastal Area in addition from 30 November 1941. He thus had the dual role of commanding field force units for a mobile role and static units for defence of vulnerable points. In December 1942 the 73rd Brigade lost its infantry battalions and was simply designated Cornwall Coastal Area. Next, Cazenove commanded
140th (4th London) Brigade in
47th (London) Infantry Division, a reserve formation, from 13 April 1943 until 31 August 1944 when it was disbanded. For his war service, Cazenove had been mentioned in despatches, awarded the American
Legion of Merit, and made a Commander of the
Order of Orange-Nassau. He was Deputy Commander of Aldershot District from 1947 to 1950, was promoted to substantive brigadier in 1948, and retired in 1950. ==Family==