Question to the Ministry of Defence:

To ask the Secretary of State for Defence, what aspects of Trident are reliant upon US support.

The UK has a longstanding, close relationship with the US on all defence nuclear issues, which has endured through many changes of Government in our two nations. One result of our close relationship is that the UK is able to procure certain non-nuclear components from the US, most notably the Trident II D5 missile, significantly reducing the cost of our nuclear deterrent capability.

Our extant long-term arrangements under the 1958 Mutual Defense Agreement and the 1963 Polaris Sales Agreement (as amended in 1982 for Trident) provide for co-operation and collaboration which has been, and continues to be, of considerable mutual benefit to both nations.

Further details can be found in Command Paper 1058: Delivering the UK’s Nuclear Deterrent as a National Endeavour at the following link:

https://www.gov.uk/government/publications/defence-nuclear-enterprise-command-paper]