Walter Douglas was a major in the Prince of Wales' Own Regiment of Yorkshire, born 8 May 1931. He was married to Penny Douglas.
Dougie, as Lethbridge-Stewart called him, had been best friends with Lethbridge-Stewart since Sandhurst and was one of the "holy trinity" of ambitious cadets alongside Leslie Johnston. Douglas had not planned on a military career, he had expected to be a market stall holder on Portobello Road.
He introduced Sally Wright to Lethbridge-Stewart, and was to be best man at their wedding. Dougie as also aware of the man's fling with Doris and was one of the few people who could get away with bringing her up.
In March 1969, Major Douglas was called in to assist Colonel Lethbridge-Stewart in the clear up after the London Event and, when Lethbridg-Stewart was on leave, took over from him. He was unaware that the Event had been an alien attack. After the clear up of the London Event, Douglas was promoted to lieutenant colonel. (PROSE: The Forgotten Son)
In April 1969, he was called in by Major General Hamilton to assist journalist Larry Greene in finding Lethbridge-Stewart, after the colonel failed to reach Tibet. They tracked down Lethbridge-Stewart's crashed plane in East Germany, although Lethbridge-Stewart was nowhere to be seen. He was on hand when Professor Travers and Anne Travers discovered that Lethbridge-Stewart was trapped in an alternative 1959, and found a way to bring him back. (PROSE: The Schizoid Earth)
By May 1969 he was stationed at County Down, dealing with riots in Northern Ireland. While back in England on leave with his wife, he was brought in to help Lethbridge-Stewart on Fang Rock, but only arrived in time to help clean-up. He, Penny, Lethbridge-Stewart and Sally later had dinner together. (PROSE: Beast of Fang Rock)