[1] He was educated at Magdalen College, Oxford[2] and afterwards worked as London editor of The Manchester Guardian.
Virginia Woolf made twenty-three pages of notes on Gretton's book as part of her background reading for her 1937 novel The Years.
[4] During the First World War he was a private in the Royal Garrison Artillery and he also served in the Labour Corps in France.
[3] From 14 June to 19 July 1929, Gretton delivered a series of broadcasts for BBC radio on the subject of "Some Makers of Modern Politics", in which he explored various Victorian statesmen and their influence.
[5] Gretton married Mary Sturge, who died in York on 15 August 1961, aged 90.