Information about the UK’s continuous at sea deterrent (CASD) and the Successor programme to replace the Royal Navy’s Trident missile Vanguard Class Submarines.
The protection and defence of the UK is a primary responsibility of the government. The government is committed to maintaining the UK’s national nuclear deterrent based on a ballistic missile submarine for as long as the global security situation makes that necessary.
The continuous at sea deterrent (CASD) has provided the United Kingdom’s ultimate security insurance policy every day for the last 46 years.
Since 1992 the 4 boats of the Vanguard Class have maintained CASD, ensuring at all times 1 submarine was deployed. As the Vanguard submarines progress to the end of their lifespan, the UK is looking at the next generation of submarines to carry forward the vital role. This is called the Successor submarine programme.
Read Defence Minister Philip Dunne’s Blog explaining why the UK needs to maintain an independent nuclear deterrent here .
The Defence Secretary, Michael Fallon, explains why the UK needs a nuclear deterrent in the video below.
Read the full National Security Strategy and Strategic Defence and Security Review 2015 here.
- Policy paper
Nuclear deterrence policy
A full list of policy and related documents is available here.
Successor submarine programme
Published: 26 February 2016
Updated: 20 December 2016
- Added The United Kingdom’s future nuclear deterrent: 2016 update to Parliament
- Added speech for The case for the retention of the UK's independent nuclear deterrent.
- Added news article.
- First published.