Alistair Lethbridge - Stewart ( The Warkeeper ' s Crown ) Alistair Conall Hamish Lethbridge - Stewart was a member of the Lethbridge - Stewart family . His father was the Honourable Hamish Lethbridge - Stewart , and his brother Archibald Hamish Lethbridge - Stewart . He was , ostensibly , the adoptive grandfather of Brigadier Alistair Gordon Lethbridge - Stewart , who was named after him . He was married to Lillian Lethbridge - Stewart ( née McDougal ) , and they had two sons , Matthew Lethbridge - Stewart , and Gordon Conall Lethbridge - Stewart , who was born in 1902 . He lived in Carmunnock , Lanarkshire in Scotland until around 1925 , with his wife and sons . ( PROSE : " The Wages of Sin " , " The Forgotten Son " , " Night of the Intelligence " , " What ' s Past is Prologue " , " The Note " ) He fathered Matthew in 1900 , and in 1902 his wife fell pregnant with a second child who they called Gordon . It was some thirteen years later that Alistair began to realise that Gordon was not , in fact , his son , but the result of a night of indiscretion between his wife and brother . He never , however , spoke of this openly with either party . ( PROSE : " The Note " ) During World War I , he worked British Intelligence in Russia but was forced to return to the United Kingdom in the aftermath of the Russian Revolution of 1917 . One of his colleagues was Bertie Stopford , the then British ambassador to Russia . ( PROSE : " The Wages of Sin " ) On 26 December , 1917 , Alistair visited the Carmunnock police station , after Gordon had tried to enlist in the army underage . While picking up his son , he met Archibald Hamish Lethbridge - Stewart , his brother , and the two of them had a drink to celebrate their offspring ' s futures . He was concerned that Gordon was looking more like Archibald as he grew , but was glad Gordon had not realised why . ( PROSE : " What ' s Past is Prologue " ) He became a grandfather in 1925 to James Lethbridge - Stewart and again to his namesake , Alistair Gordon Lethbridge - Stewart , in 1929 . ( PROSE : " The Forgotten Son " ) Another account said that he became a grandfather when Alistair was born in India in 1930 . ( PROSE : " Blood Heat " , " Island of Death " ) Lethbridge - Stewart frequently pressurised the younger Alistair into following his footsteps and joining the British military . For Christmas 1938 , he gave Alistair a box of toy soldiers and then asked him , " What do you want to be when you grow up ? " Alistair was not pleased with his present . After his eldest son was confirmed as Missing in Action in May 1945 , Alistair received a letter from the family solicitor , who had held the letter since April 1938 . The letter told him that Gordon had long since learned that truth of his biological father , but regardless he still considered Alistair his " real " father . After this , Alistair decided that perhaps it was time to talk to Archibald and reveal the secret to their offspring , and their grandchildren . ( PROSE : " The Note " ) On his deathbed , he told a commissioned Alistair that he was proud of him . ( COMIC : " The Warkeeper ' s Crown " ) Behind the scenes . As confirmed by Mark Gatiss , the character of Archibald Hamish Lethbridge - Stewart , whom he portrayed in TV : " Twice Upon a Time " was intended to be the grandfather of Alistair Gordon Lethbridge - Stewart . However , the episode itself does not explicitly state their relations . However , Andy Frankham - Allen , as Creative Director of the Haisman Estate , made it clear that neither the Haisman Estate nor Henry Lincoln , copyright owners of the Lethbridge - Stewart IP , consider the character as the grandfather , but that their official stance is the character is the grandfather ' s brother . Since that time , however , Frankham - Allen convinced the Haisman Estate to reach a compromise , and as a result it was revealed in the short story , The Note , that Gordon Lethbridge - Stewart was the illegitimate son of Archibald . Whether this means the Brigadier is aware has yet to be revealed .