On 27/28 April 1918 at the Gavrelle Sector, France, when Lieutenant McKean's party was held up at a block in the communication trench by intense fire, he ran into the open, leaping over the block head first on top of one of the enemy. Whilst lying there, he was attacked by another with a fixed bayonet. He shot both of these men, captured the position, then sent back for more bombs, and until they arrived he engaged the enemy single-handed. He then rushed a second block, killing two of the enemy, capturing four others, and driving the remainder into a dug-out, which he then destroyed.