He was made a brevet colonel in 1932 and promoted to lieutenant-colonel on 24 November 1936. In 1937 Roberts became CO of the 1st Battalion, Royal Warwickshires and went with the battalion to India. The following year he became commander of the Poona Brigade of the Indian Army, and was granted the local rank of brigadier from 9 April 1937 until 8 November 1937, before reverting to colonel, when he relinquished command. Returning to England, he was promoted to the rank of major-general on 1 June 1939 (with seniority backdated to 13 June 1939), three months before the outbreak of the Second World War, and became General Officer Commanding (GOC) of the 48th (South Midland) Infantry Division, a Territorial Army (TA) formation. Aged just 48, he was one of the youngest divisional commanders in the British Army, only Major-General The Hon. Harold Alexander, GOC of the 1st Infantry Division, and Major-General William Holmes, GOC of the 42nd (East Lancashire) Infantry Division, being younger.