Breen was seconded from the Royal Irish Regiment to the Royal Flying Corps in 1915. He transferred from the
British Army to the RAF in 1918 as a captain in 1918. He was promoted to
squadron leader in 1925 with
No. 24 Squadron RAF. He was posted to Iraq as commander of an armoured car wing. He then commanded
No. 84 Squadron RAF and
No. 33 Squadron RAF before a period of study at the
Imperial Defence College. As a
wing commander in 1935 he was attached to the Sudan Defence Force in Khartoum. From 27 June 1940 he was appointed Air Officer Commanding
No. 1 Group at
RAF Bomber Command and served in this post during the
Battle of Britain, but in December 1940 he was moved to the Air Ministry on promotion to
air commodore. He later served as Director General of Personnel for the RAF and as Head of the Postwar Planning Executive before retiring as an air marshal on 2 May 1946. He died in 1964 aged 68. ==References==