Career
He served in World War I and in the Territorial Army, and was Administrator of the colony of Western Samoa (now Samoa) 1928–1931. His rule was marked by the mass shooting of eleven Samoans from the indepententist Mau movement, including its acting leader Tupua Tamasese Lealofi III, on the 29 December 1929. He was the son of William Shepherd Allen, an Member of Parliament in both the United Kingdom and New Zealand.
His mother was Elizabeth Penelope Candlish, daughter of John Candlish.
Allen was appointed a Knight Commander of the Order of the British Empire (Knight Commander of the Order of the British Empire) in the 1933 Birthday Honours. In 1935, he was awarded the King George V Silver Jubilee Meda
On 4 November 1964, Allen suffered a heart attack while driving near Maramarua, and both he and his housekeeper, Elma Jessie Brunton, died in the resulting crash.