 The son of Brigadier General Walter Allason DSO & Bar (1875–1960) by his wife Katherine Hamilton Poland, daughter of Vice-Admiral James Augustus Poland, James Allason was raised primarily by a great-aunt following the death of his mother in 1913 protecting the infant James in a fall down stairs.Walter Allason was grandson of the architect Thomas Allason.He was educated at Haileybury and Imperial Service College and the Royal Military Academy, Woolwich.