[4] After attending the Staff College, Camberley from 1934 to 1935, he served as Deputy Director of Military Operations and Intelligence in India from 17 September 1939 to 28 January 1941.[1][2] In January 1941, Roberts was appointed GSO1 (Chief Staff Officer) of the 10th Indian Infantry Division, which was then forming at Ahmednagar in India.[10] Roberts returned to 10th Indian Division after completing what his divisional commander, Major General William Slim, later described as "one of the best single-handed jobs any officer of his then rank had performed in the war".[11] As chief staff officer, Roberts played an important role in the 10th Indian Division's involvement in the Euphrates expedition during the Syria–Lebanon campaign in July 1941 and the Anglo-Soviet Invasion of Iran a month later, earning him promotion to Commanding Officer of the division's 20th Indian Infantry Brigade in Iraq in January 1942.[1] As the threat of a Japanese invasion of Ceylon receded, 16th Infantry Brigade was redeployed in July 1943 while Roberts was appointed chief staff officer (Brigadier General Staff) of IV Corps at Imphal commanded by Lieutenant General Geoffry Scoones[1][12] and which formed part of Slim's Fourteenth Army.