Gilbert lived in Sevonoaks, He entered the war in France on the 14th August 1914. He was awarded the Distinguished Conduct Medal "For conspicuous gallantry and devotion to duty when in the collection and evacuation of wounded he showed a complete disregard of personal danger, and brought in Capt. Hancock, who was lying severely wounded, exposed to machine gun fire, although in great danger of being cut off by the enemy. Later, during the retirement, he rendered valuable service in organizing relay posts and evacuating the wounded.