Captain Douglas Fairbairn was sent to be the commanding officer of Jamie Colquhoun's regiment a few weeks before July 1916, before the Battle of the Somme. He was giving his men a tot of rum for courage before the battle. He was still not used to the war, and his hands were shaking when he was pouring the rum. He reported directly to Atkinson.
He suspected the Tenth Doctor and Gabby Gonzalez of being spies, prompting him to pull a gun on the Doctor. However, Gabby convinced him that they were sent by a "Lieutenant Colonel Brooks". He tried to get confirmation from headquarters, but the phone lines are broken. Fairbairn sent John McHugh to fix them.
When the remainder of the regiment escaped following the attack by the Weeping Angels, Fairbairn stayed behind to hold the Angels off. He was immediately circled by the angels and fired his pistol until he ran out of bullets and was killed. (COMIC: The Weeping Angels of Mons)