Robertson was born on 23 May 1890 at Lowestoft, Suffolk. He died on 21 April 1963 at Cambridge. He was the youngest of the six children of Dr James Robertson, schoolmaster, clergyman and fellow of Jesus College, Cambridge, and his wife Constance Elizabeth Wilson. The Robertsons were of Scottish by descent but long domiciled in England, and there were English connections on his mother's side.
From The Biographical Dictionary of British Economists in Oxford Reference.