He is distantly related to William Armstrong, later Baron Armstrong of Cragside. Cragside is a mansion in Northumberland which was the first to be lit by electricity in the late 1860s.
Second cousin of the actress Imogen Stubbs (his grandfather was brother of her grandmother).
By an extraordinary coincidence, he bought the same first single and album as his Pointless (2009) co-presenter Richard Osman (the first album he bought was "Kings of the Wild Frontier" by Adam and the Ants and the first single he bought was "Swords of a Thousand Men" by Tenpole Tudor).
Has three sons, Edward, Patrick and Rex.
His father is Angus Armstrong (a GP) and his mother is Virginia McCausland. Has an older brother, Dominic and an older sister, Alice (b. 1967).