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:''This article covers the entire British Trident nuclear weapons programme. For a technical discussion of the Trident I and Trident II missiles, see Trident (missile)'' The UK Trident programme encompasses the development, procurement and operation of the current generation of British nuclear weapons, and the means to deliver them. Trident itself is an operational system of four Vanguard-class submarines armed with Trident II D-5 ballistic missiles, able to deliver thermonuclear warheads from multiple independently-targetable reentry vehicles (MIRVs). It is the most expensive and the most powerful capability of the British military forces. Operated by the Royal Navy and based at Clyde Naval Base on Scotland's west coast, at least one submarine is always on patrol to provide a continuous at-sea deterrent. Under the terms of the 2010 Strategic Defence and Security Review, each will be armed with a maximum of eight missiles and 40 warheads, although their capacity is much larger. The UK Trident programme was announced in July 1980, and patrols began in December 1994. Since 1998, Trident has been the only British nuclear weapon system in service. Its stated purpose is to provide "the minimum effective nuclear deterrent as the ultimate means to deter the most extreme threat."〔 Trident replaced the earlier submarine-based Polaris system, which was in operation from 1968 to 1996. Work on a potential replacement for the Trident system has begun, although no final decisions have been taken. ==History== In 1980 the Government of the United Kingdom announced its intention to replace its independent nuclear deterrent, and formally sought permission to acquire the Trident I C-4 missile then in service with the US Navy.〔 Trident would replace the UK Polaris programme system of four Resolution-class submarines, equipped with the US-built Polaris A3 missile. These missiles were originally armed with triple ET.317 warheads aimed at a single target, later upgraded by the UK Chevaline programme to two hardened warheads accompanied with countermeasures. Following the acceleration of the US Trident II D-5 programme, the existing Polaris Sales Agreement was modified in 1982 to permit the supply of the more advanced missiles. Under the agreement, the UK would lease 65 Trident II D-5 missiles from a larger pool of such weapons based at Naval Submarine Base Kings Bay in the United States. The US would retain responsibility for the maintenance of the missiles, and the UK would manufacture its own warheads and submarines.〔 The entire project was projected to cost £5 billion, including the four submarines, the missiles, new facilities at Coulport and Faslane and a five per cent contribution to Trident II D-5 research and development. The option for a fifth submarine was discussed at the time but later discounted, and the number of missiles leased was later reduced from 65 to 58. The UK programme's future was secured the following year when the Conservative government won the general election, defeating the Labour opposition which had pledged to cancel the programme. The Vanguard-class submarines were built between 1986 and 1998 by Vickers Shipbuilding and Engineering at Barrow-in-Furness, Cumbria. The first British Trident missile was test-fired from HMS Vanguard on 26 May 1994, and Vanguard went on to begin the first Trident patrol in December of that year. According to the Royal Navy, at least one submarine has always been on patrol ever since. Trident has been the UK's sole nuclear weapons system since the retirement of the WE.177 tactical nuclear weapon following the 1998 Strategic Defence Review. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「UK Trident programme」の詳細全文を読む スポンサード リンク
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