John Slessor

Marshal of the Royal Air Force Sir John Cotesworth Slessor, GCB, DSO, MC (3 June 1897 – 12 July 1979) was a senior commander in the Royal Air Force (RAF), serving as Chief of the Air Staff from 1950 to 1952. As a pilot in the Royal Flying Corps during the First World War, he saw action with No. 17 Squadron in the Middle East, earning the Military Cross, and with No. 5 Squadron on the Western Front, where he was awarded the Belgian Croix de Guerre. Between the wars he commanded No. 4 Squadron in England, and No. 3 (Indian) Wing, earning the Distinguished Service Order for operations with the latter in Waziristan. In 1936, he published Air Power and Armies, which examined the use of air power against targets on and behind the battlefield.

Slessor held several operational commands in the Second World War. As Air Officer Commanding Coastal Command in 1943 and 1944, he was credited with doing much to turn the tide of the Battle of the Atlantic through his use of long-range bombers against German U-boats. He was knighted in June 1943. In the closing stages of the war he became Commander-in-Chief RAF Mediterranean and Middle East and deputy to Lieutenant General Ira Eaker as Commander-in-Chief Mediterranean Allied Air Forces, conducting operations in the Italian Campaign and Yugoslavia. Slessor went on to serve in the RAF's most senior post, Chief of the Air Staff, in the early 1950s, and was considered a strong proponent of strategic bombing and the nuclear deterrent. In retirement he published two more books, including an autobiography, and held ceremonial appointments in Somerset.

The son of Major Arthur Kerr Slessor and Adelaide Slessor (née Cotesworth), Slessor was born in Ranikhet, India, on 3 June 1897, and educated at Haileybury. Lame in both legs as a result of polio, he was rejected for army service in 1914 and received a commission as a second lieutenant in the Royal Flying Corps on 6 July 1915 only with the help of family connections. He was appointed to the Special Reserve as a flying officer on 9 September 1915, and confirmed in his rank of second lieutenant on 28 September. Slessor saw action with No. 17 Squadron in Egypt and the Sudan, where he was credited with arresting the escape of Sultan Ali Dinar and 2,000 men on 23 May 1916, following the Sultan's defeat at Beringia. He was mentioned in despatches on 25 October before being wounded in the thigh and invalided back to England.

Slessor was promoted to the temporary rank of captain on 1 December 1916. Awarded the Military Cross on 1 January 1917, he returned to combat in April as a flight commander with No. 5 Squadron on the Western Front. The squadron converted from Royal Aircraft Factory BE.2s to R.E.8s soon afterwards. Promoted to the substantive rank of lieutenant on 1 July 1917, Slessor was appointed a Chevalier of the Belgian Order of Leopold on 24 September, and awarded the Belgian Croix de Guerre on 11 March 1918. He transferred to the newly formed Royal Air Force in April 1918 and, having been promoted to the temporary rank of major on 3 July 1918, was posted to the Central Flying School at Upavon as an instructor on 14 July 1918.

Having left the RAF as a flight lieutenant on 21 August 1919, Slessor applied to rejoin and was offered a short-service commission at the same rank on 24 February 1920. In May 1921, he became a flight commander with No. 20 Squadron, which operated Bristol Fighters on the North-West Frontier of India. He joined the staff at the Directorate of Training and Staff Duties in the Air Ministry in February 1923. The same year, he married Hermione Grace Guinness; they had a son and a daughter. He attended the RAF Staff College, Andover, in 1924, and was promoted squadron leader on 1 January 1925.

Slessor commanded No. 4 (Army Cooperation) Squadron, which flew Bristol Fighters out of RAF Farnborough, from April 1925 to October 1928, when he joined the air planning staff at the Directorate of Operations and Intelligence at the Air Ministry. He attended the Staff College, Camberley, in 1931, and was appointed RAF Directing Staff Officer there in January 1932. Slessor was promoted acting wing commander on 1 January 1932 (substantive on 1 July). He became Officer Commanding No. 3 (Indian) Wing at Quetta in March 1935, and was awarded the Distinguished Service Order for operations in Waziristan between 25 November 1936 and 16 January 1937.

In 1936, Slessor published Air Power and Armies, an examination of the use of air power against targets on and behind the battlefield. In this work he advocated army co-operation, interdiction to cut off enemy reinforcements and supply, and the use of aerial bombardment as a weapon against enemy morale. He did, however, acknowledge the limitations of his theory, stating:

...the conditions envisaged throughout [this book] are those of a campaign on the land in which the primary problem at the time is the defeat of an enemy army in the field. ... in a war against a great Naval power at sea, or when the principle threat to the Empire at the time is the action of hostile air forces against this country or its possessions, the aim and objectives of the air forces of the Empire will not be the same as described in this book.