Successor submarine programme: the facts

Successor is the replacement programme for the Royal Navy’s Trident missile Vanguard Class submarines which form the UK’s nuclear deterrent.

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.

See the Successor factsheet below to learn more.

Read Defence Minister Philip Dunne’s Blog explaining why the UK needs to maintain an independent nuclear deterrent here.

Successor submarine continuing at sea deterrence


  1. Successor submarine programme: factsheet

    • Policy paper

Background information

UK nuclear deterrent policy.

  1. Treaty on the Non-Proliferation of Nuclear Weapons (London, 1/7/1968)

    • International treaty
  2. Written ministerial statement on the Trident Alternatives Review

    • Statement to Parliament
  3. Trident alternatives review

    • Research and analysis
  4. The United Kingdom’s future nuclear deterrent: the submarine initial gate parliamentary report

    • Policy paper