Editing Polaris Sales Agreement (section)

==Trident==
{{main|Trident nuclear programme}}
The Polaris Sales Agreement provided an established framework for negotiations over missiles and re-entry systems.{{sfn|Stoddart|2008|p=89}} The legal agreement took the form of amending the Polaris Sales Agreement through an exchange of notes between the two governments so that "Polaris" in the original now also covered the purchase of Trident. There were also some amendments to the classified annexes of the Polaris Sales Agreement to delete the exclusion of penetrating aids.{{sfn|Stoddart|2014|pp=154–155}} Under the Polaris Sales Agreement, the United Kingdom paid a five per cent levy on the cost of equipment supplied in recognition of US research and development costs already incurred. For Trident, a payment of $116 million was substituted.<ref>{{cite web |url=http://treaties.fco.gov.uk/docs/pdf/1983/TS0008.pdf|title=Exchange of Notes concerning the Acquisition by the UK of the Trident II Weapon System under the Polaris Sales Agreement |series=Treaty Series No. 8 |publisher=Her Majesty's Stationery Office |date=March 1983 |access-date=6 November 2017 }}</ref> The United Kingdom procured the Trident system from America and fitted them to their own submarines, which had only 16 missile tubes like Polaris rather than the 24 in the American {{sclass|Ohio|submarine|4}}. The first {{sclass|Vanguard|submarine|2}}, {{HMS|Vanguard|S28|6}}, entered operational service in December 1994, by which time the [[Cold War]] had ended.{{sfn|Stoddart|2014|pp=245–246}}