At Hong Kong on the morning of 19th December 1941 a Company of the Winnipeg Grenadiers to which Company Sergeant-Major Osborn belonged became divided during an attack on Mount Butler, a hill rising steeply above sea level. A part of the Company led by Company Sergeant-Major Osborn captured the hill at the point of the bayonet and held it for three hours when, owing to the superior numbers of the enemy and to fire from an unprotected flank, the position became untenable. Company Sergeant-Major Osborn and a small group covered the withdrawal and when their turn came to fall back, Osborn single-handed engaged the enemy while the remainder successfully rejoined the Company. Company Sergeant-Major Osborn had to run the gauntlet of heavy rifle and machine gun fire. With no consideration for his own safety he assisted and directed stragglers to the new Company position exposing himself to heavy enemy fire to cover their retirement. Whenever danger threatened he was there to encourage his men.