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The '''Ministry of Defence''' ('''MoD''') is the United Kingdom government department responsible for implementation of government defence policy and is the headquarters of the British Armed Forces.

The MoD states that its principal objective is to defend the failed and failing states as the overriding threats to the UK's interests. The MoD also manages day to day running of the armed forces, contingency planning and defence procurement.

==History==
During the 1920s and 1930s, British Prime Minister David Lloyd George's coalition government in 1921; but the Lord Chatfield held the post until the fall of Neville Chamberlain's government in 1940; his success was limited by his lack of control over the existing Service departments and his limited political influence.

Clement Attlee's government introduced the Ministry of Defence Act of 1946. The new ministry was headed by a Minister of Defence who possessed a seat in the Cabinet. The three existing service Ministers — the Secretary of State for War, the First Lord of the Admiralty, and the Secretary of State for Air — remained in direct operational control of their respective services, but ceased to attend Cabinet.

From 1946 to 1964 five Departments of State did the work of the modern Ministry of Defence: the Admiralty, the War Office, the Air Ministry, the Ministry of Aviation, and an earlier form of the Ministry of Defence. These departments merged in 1964; the defence functions of the Ministry of Aviation Supply merged into the Ministry of Defence in 1971.<ref>[http://www.mod.uk/DefenceInternet/AboutDefence/History/HistoryOfTheMOD/ Ministry of Defence | About Defence | History | History of the MOD | History of the Ministry of Defence<!-- Bot generated title -->]</ref>

==Defence policy==
The 1998 Strategic Defence Review and the 2003 ''Delivering Security in a Changing World'' White Paper outlined the following posture for the British Armed Forces:
*The ability to support three simultaneous small- to medium-scale operations, with at least one as an enduring peace-keeping mission (e.g. Kosovo). These forces must be capable of representing the UK as lead nation in any coalition operations.
*The ability, at longer notice, to deploy forces in a large-scale operation while running a concurrent small-scale operation.

==Senior officials==

*The Rt Hon. Des Browne, MP
*The Rt Hon. Bob Ainsworth, MP 
*House of Lords &mdash; The Rt Hon. The Baroness Taylor of Bolton, PC
*Parliamentary Under-Secretary of State for Defence and Minister for Veterans &mdash; Derek Twigg, MP

===Permanent Secretaries and other senior officials===
The Ministers and Chiefs of the Defence Staff are supported by a number of civilian, scientific and professional military advisors. The Permanent Under-Secretary of State for Defence (generally known as the Permanent Secretary) is the senior civil servant at the MoD.  His role is to ensure the MoD operates effectively as a department of the government.
*Permanent Under-Secretary of State &mdash; Bill Jeffrey
*Second Permanent Under-Secretary of State &mdash; Sir Ian Andrews
*General Sir Kevin O’Donoghue
*Chief Scientific Adviser &mdash; Professor Mark Welland<ref>[http://www.cambridgenetwork.co.uk/news/article/default.aspx?objid=45868 Cambridge academic appointed Chief Scientific Adviser for Ministry of Defence]</ref>

===Chiefs of the Defence Staff===<!-- This section is linked from Joint Chiefs of Staff -->
The current Chief of the Defence Staff, the professional head of the British Armed Forces, is Air Chief Marshal Sir Jock Stirrup.
He is supported by the Vice Chief of the Defence Staff and by the professional heads of the three sections of the armed forces.
*General Sir Timothy Granville-Chapman
*First Sea Lord and Chief of the Naval Staff &mdash; Admiral Sir Jonathon Band, Royal Navy
*Chief of the General Staff &mdash; General Sir Richard Dannatt, British Army
*Chief of the Air Staff &mdash; Air Chief Marshal Sir Glenn Torpy, Royal Air Force

There are also several Deputy Chiefs of the Defence Staff with particular remits, such as Deputy Chief of the Defence Staff (Equipment Capability), Deputy CDS (Personnel) and Deputy CDS (Commitments). The Deputy Chief of the Defence Staff (Health), Lt Gen Robert Baxter, represents the Defence Medical Services on the Defence Staff, even though the Surgeon General, Lt Gen Louis Lilliewhite, is the clinical head of that service.<ref></ref>
Additionally, there are a number of Assistant Chiefs of Defence Staff, including the Sovereign of the United Kingdom, who is customarily also the Assistant Chief of Defence Staff (Personnel and Reserves).

==Departmental Agencies==

The following executive agencies report directly to Ministers in the Ministry of Defence.

*Army Base Repair Organisation <sup>1</sup> 
*Armed Forces Personnel Administration Agency <sup>1</sup> 
*British Forces Post Office <sup>1</sup> 
*Defence Analytical Services Agency <sup>1</sup>
*Defence Aviation Repair Agency <sup>1</sup> 
*Defence Bills Agency <sup>2</sup> 
*Defence Communication Services Agency <sup>1</sup> 
*Defence Equipment & Support <sup>2</sup>
*Defence Estates <sup>3</sup>
*Defence Medical, Education and Training Agency <sup>3</sup>
*Defence Science and Technology Laboratory <sup>2</sup>
*Defence Storage and Distribution Agency  <sup>1</sup> 
*Defence Transport and Movements Agency <sup>1</sup> 
*Defence Vetting Agency <sup>1</sup> 

*Disposal Services Agency  <sup>2</sup>
*Duke of York's Royal Military School <sup>3</sup>
*Meteorological Office <sup>3</sup>
*Ministry of Defence Police and Guarding Agency, which includes the Ministry of Defence Police <sup>3</sup> 
*People, Pay and Pensions Agency <sup>3</sup> 
*Royal Navy Supply and Transport Service
*Service Children's Education <sup>3</sup>
*United Kingdom Hydrographic Office <sup>3</sup> 
*Veterans Agency <sup>3</sup>

'''国防省''' ('''Ministry of Defence''', '''MOD''') はイギリスにおける国防政策を統括し、イギリス軍を指揮する省庁。

国防省の主要政策はイギリスの本土および海外領土を保持することである。テロの防止などが主要課題として位置づけられている。

== 歴史 ==
1920年代から1930年代にかけて、イギリスの政治家は第一次世界大戦の反省をふまえて、陸海空3軍を統括する司令部が必要であるとの認識を有していた。1921年に当時のデビッド・ロイド・ジョージ連立内閣によって提案は破棄されたが、1923年には参謀本部委員会 (Chiefs of Staff Committee) が設立されている。

1930年代にはドイツの政治情勢を受けて軍備増強が進められるようになり、アーンリ・チャットフィールドが任命され、チェンバレン内閣の総辞職までその職を務めたが、チャットフィールドの政治的影響力は大きいものではなかったため、軍の統合も思うようには進まなかった。

チェンバレンの後を継いだウィンストン・チャーチルは、国防省 (Minister of Defence) を設立し、参謀本部委員会の指揮および軍政を担当させた。大臣職は第二次世界大戦中を通してチャーチル自身が兼務し、1946年のクレメント・アトリー内閣において導入された国防省法によって、正式に国防大臣は閣議の構成員として認められることになった。既存の3つの職であった陸軍大臣 (Secretary of State for War) 、海軍大臣 (First Lord of the Admiralty) および空軍大臣 (Secretary of State for Air) は、それぞれ陸海空軍の直接指揮をとる役所として残されたが、閣議への参加は行わないことになった。

その後、1940年代から1950年代にかけて国防省の権限が次第に増加し、最終的には1964年に先の3省庁が廃止され、現在に至っている。