An official website of the United States government
Here's how you know
A .mil website belongs to an official U.S. Department of Defense organization in the United States.
A lock (lock ) or https:// means you’ve safely connected to the .mil website. Share sensitive information only on official, secure websites.

WASHINGTON (June 21, 2023) - A one-page multi-use banner graphic representing Strategic Systems Programs, United Kingdom activity. This graphic was created for use on the new SSP website but can also be utilized as part of a recruitment materials or mission advertisement as appropriate (U.S. Navy Graphic by Oliver Thompson).


The Polaris Sales Agreement, originally signed April 6, 1963, and amended in 1982, is a bilateral international agreement between the United States and the United Kingdom.

The Polaris Sales Agreement between the Government of the United Kingdom of Great Britain and Northern Ireland and the Government of the United States of America, more commonly referred to as the Polaris Sales Agreement or PSA, arose from talks between US President John F. Kennedy and UK Prime Minister Harold Macmillan in Nassau, Bahamas in 1962. The resulting joint communiqué, known as the Nassau Agreement, was issued on December 21, 1962. It established the basic policy and terms underlying the sale of Polaris missiles to the United Kingdom and aimed to develop a multilateral North Atlantic Treaty Organization (NATO) nuclear force. Specific language within the Nassau Agreement highlighted the NATO purpose, stating “…except where Her Majesty’s Government may decide that supreme national interests are at stake,” submarines of the United Kingdom equipped with the Polaris missile would “… be used for the purposes of international defense of the Western Alliance in all circumstances.” The PSA, together with the Mutual Defense Agreement,  establish the framework crucial for enabling and maintaining the United Kingdom’s strategic deterrent.

President John F. Kennedy and UK Prime Minister Harold Macmillan

The PSA was amended in 1980 to facilitate the UK’s purchase of the Trident I (C4) missile. However, in order to maintain commonality with the US after its decision to develop and procure the Trident II D5 missile, the UK requested in March 1982 to modify the agreement for the US to sell them the Trident II instead of the Trident I. The first strategic patrol with a Trident II D5 Strategic Weapon System by a ballistic missile submarine of the UK occurred on HMS Vanguard in December 1994. 

In 2006 the US and the UK agreed to maintain compatibility between their successor submarines and strategic weapon systems, ushering in what became a common effort to design, develop, and produce a new launcher system in the form of a Common Missile Compartment in general accordance with the terms and provisions of the PSA. Current bilateral lines of effort under the PSA include sustainment of the Life Extended Trident D5 Strategic Weapon System (D5LE) deployed on Vanguard Class ballistic missile submarines (SSBNs) of the UK and Ohio Class SSBNs of the US and development and construction of a Common Missile Compartment (CMC) to house the Strategic Weapon System in the Columbia Class SSBNs being built by the US and the Dreadnought Class SSBNs being built by the United Kingdom.


Through the PSA and our partnership with the US, the UK has received invaluable support to construct and maintain the Strategic Weapons Systems that have formed the totality of our independent, sovereign strategic deterrent since the Royal Navy took on that role in 1969. For sixty years we have cooperated under the Polaris Sales Agreement to protect our people, safeguard our coastlines, assure our allies, and support home-grown industries, and we will continue to do so for as long as necessary. What started as an agreement for the UK to purchase the Polaris Weapons System later extended to the Trident strategic weapon system, and remains one of the most important intergovernmental agreements in the history of our two nations. We are now developing the common missile compartment as part of the platform for our third generation of strategic submarines, our Dreadnought Class and the US Columbia Class, which are set to be the most advanced ballistic submarine platforms ever constructed.


Voices of the Polaris Sales Agreement


Google Translation Disclaimer

Guidance-Card-Icon Dept-Exclusive-Card-Icon