Sam Bishop's great-grandfather

From Tardis Wiki, the free Doctor Who reference

Sam Bishop's great-grandfather was a British Army soldier who fought with the Eighth Army in North Africa during World War II, serving in battlefronts such as El-Alamein, Tobruk, and Gazala. Following the war, he would regale the young Sam Bishop with war stories of his time there, inspiring him to eventually join UNIT. (AUDIO: Earthfall)