Born on 24 February 1896 and educated at Southend High School for Boys and King's College London,[1] he served in the British Army's Essex Regiment during the First World War.
Coulshaw served as a combatant with the 10th Essex. He joined as a private in September 1914, was commissioned in January 1916, and ended the war as an acting captain. He was wounded at Gallipoli, and the bullet which lodged near his lower ribs could not be extracted. (In 1922, he was still in pain from the wound). He then fought on the Somme, and was awarded a Military Cross in April 1917.
For conspicuous gallantry and devotion to duty. He led a platoon in the attack in the most gallant manner, reached his objective, and consolidated his position under very heavy hostile shallfire.[2]
Later that year, he was wounded at Ypres by a shell which caused slight damage to his throat. In 1920 at Cologne, he fell from a horse and a blow to the forehead led to headaches and bad memory.[3]