[4][6] Just less than two months after his arrival in France, Roberts was already proving himself in action, which resulted in his being awarded the Distinguished Service Order (DSO) while leading a trench raid.

[4][11] He was 26 years old, and an acting lieutenant-colonel in the 1st Battalion, Worcestershire Regiment, British Army during the First World War when the following deed took place for which he was awarded the VC.

Lieutenant-Colonel Roberts showed exceptional military skill during the period 22 March – 2 April 1918, in the German spring offensive, west of the Somme and at the village of Pargny, France.

During continuous operations which covered over twelve days Lt-Col Roberts showed most conspicuous bravery, exceptional military skill in dealing with the many very difficult situations of the retirement, and amazing endurance and energy in encouraging and inspiring all ranks under his command.

[14] Returning to England, Roberts attended the Staff College, Camberley, entering in January 1921, shortly afterwards being made an Officer of the Order of the British Empire (OBE), and graduating in December 1922.

[1] Among his many fellow students there were Eric Costin, James Gammell, John Priestman, Edward Alban, Merton Beckwith-Smith, Russell Gurney, Francis Nosworthy, Giffard Martel, John Kennedy, Ridley Pakenham-Walsh, Ralph Eastwood, Edwin Morris, Eric Miles, Robert Naylor, Thomas Corbett, Ernest Squires, Austin Miller, William Baker and Edmund Osborne, all of whom would, like Roberts, become general officers.

[4][11] His next appointment was as a General Staff Officer Grade 3 (GSO3) with the Iraqi Army and, for his service in Southern Kurdistan, was promoted to brevet lieutenant-colonel.

However, in October, Roberts handed over command of the division to Major-General Andrew Thorne and retired from the army on 16 December 1939,[20] three months after the outbreak of the war, after twenty-eight years of military service.