[5] On 16 September 1918 he was awarded the Military Cross for his actions during the retreat of the British Army in 1918; the citation read: For conspicuous gallantry and devotion to duty.

During a fortnight's operations of a most arduous description, his services in maintaining communication between brigade headquarters and the front line were most valuable, and his example of fine personal courage and coolness under heavy fire, worthy of the highest praise.

On one occasion, having been unable to find the battalion to whom he was to convey orders for retirement, he returned a second time, but encountered an enemy patrol, who opened a heavy fire.

Eluding the patrol, he came across one of our wounded, whom he helped to get on to his motor-cycle and managed to convey back to safety, though all the time being subjected to heavy fire.

Hopkinson left the army shortly after the end of the conflict, and in 1919 enrolled in Gonville and Caius College, Cambridge, where he studied for a civil engineering degree.

[10] He began studying for entry into the Staff College, Camberley, then considered as almost essential for future advancement in the army, and eventually attained a place in the institution in January 1930.

In 1936 he returned to his regiment and commanded a rifle company as a brevet major, but, possibly unhappy at the slow rate of promotion during times of peace, in February 1937 he once again retired from the army,[12] taking a job in a civil engineering firm that had operations in Turkey.

[19] On 6 April 1943 Hopkinson was promoted to the acting rank of major general,[20] and succeeded Browning in command of the 1st Airborne Division, which began to depart for Algeria at around the same time.