Project E was a joint project between the United States and the United Kingdom during the cold war to provide nuclear weapons to the British Royal Air Force (RAF) prior to Britain's own nuclear weapons becoming available. Later sometimes used more widely to refer to similar arrangements for the British Army of the Rhine.
Although Britain sought an independent nuclear deterrent during the 1950s, it only possessed ten atomic weapons in 1955 and 14 in 1956. Project E provided RAF Bomber Command with weapons to compensate. The first record of the project was in 1958 concerning the provision of Mk 7 weapons to be carried by the Canberra bomber.
Later, Mk 5 weapons were provided for the V bomber force. This provision was problematic for the RAF since United States Air Force (USAF) personnel had guardianship of these weapons at all times and they could not be dispersed to dispersal airfields as the RAF desired. As a result the weapons were returned to the United States as soon as possible when British-made nuclear and thermonuclear weapons became available. In the United Kingdom, Project E came to an end in 1965, while in forces assigned to the North Atlantic Treaty Organization it lasted until 1969. It was replaced by the NATO nuclear sharing concept for tactical nuclear weapons, which, for example, included the provision of B57 nuclear depth bombs for the Avro Shackleton and Hawker Siddeley Nimrod until 1992.
President Dwight D. Eisenhower stated:
The United States Government welcomes the agreement to coordinate the strike plans of the United States and United Kingdom bomber forces, and to store United States nuclear weapons on RAF airfields under United States custody for release subject to decision by the President in an emergency. We understand that for the present at least these weapons will be in the kiloton range. The United Kingdom forces could obviously play a much more effective part in joint strikes if the United States weapons made available to them in emergency were in the megaton range, and it is suggested that this possibility might be examined at the appropriate time."
When Vickers Valiant aircraft were allocated to SACEUR in 1960 they carried either B28 or B43 thermonuclear weapons. When co-located with non SACEUR squadrons the SACEUR squadrons were often fenced off with six foot fences on the QRA pads. These were allowed to be carried by the RAF under control of SACEUR on the same basis as Project E weapons carried by the RAF, i.e. U.S. guardians present at all times. This of course came to an end when all the Valiants were grounded on 9 December 1964. The B28 bomb later became famous as a result of the Palomares incident in 1966.
- Richard Moore (March 2004). The Real Meaning of the Words: a Pedantic Glossary of British Nuclear Weapons (PDF). Mountbatten Centre for International Studies, University of Southampton. Retrieved 2016-02-14.
- Young, Ken (Spring 2007). "A Most Special Relationship: The Origins of Anglo-American Nuclear Strike Planning". Journal of Cold War Studies. 9 (2): 5–31. doi:10.1162/jcws.2007.9.2.5.
- RAF Nuclear Deterrent Forces. The Stationery Office. 1996. p. 572. ISBN 0-11-772833-0.
- Andy Leitch. US Mk-5 atomic bomb with the RAF. Vulcans in Camera. Retrieved 2008-12-23.
- RAF Nuclear Deterrent Forces. The Stationery Office. 1996. pp. 262–263. ISBN 0-11-772833-0.
- RAF Nuclear Deterrent Forces. The Stationery Office. 1996. pp. 258–259. ISBN 0-11-772833-0.
- B28 Nuclear bomb (United States). Jane's Information Group. Retrieved 2008-11-10.
- RAF Nuclear Deterrent Forces. The Stationery Office. 1996. pp. 368–370, 500. ISBN 0-11-772833-0.
- Wynn, Humphrey. RAF Nuclear Deterrent Forces. ISBN 0-11-772833-0.