Mrs Smith was the mother of Mike Smith. Living in the Shoreditch area, she ran a boarding house where the Seventh Doctor and Ace stayed during the Shoreditch Incident.
Her son Mike was killed when he confronted Ace back in the boarding house. He answered a knock at the door and was killed by the Girl. Mrs Smith attended her son's funeral with Group Captain Gilmore.
Ace suspected Mrs Smith having prejudiced views after Ace found a sign hanging in her living room window reading "NO COLOUREDS". (TV: Remembrance of the Daleks)