Question to the Ministry of Defence:

To ask the Secretary of State for Defence, pursuant to the answer of 16th December 2025, to question 98210 on Submarines: Decommissioning, what is the schedule for (a) defueling the 12 remaining decommissioned submarines and (b) dismantling all remaining submarines.

The twelve decommissioned, first generation Pressurised Water Reactor (PWR1) submarines awaiting defuel in Devonport will dock in a specialised, licensed dock in Devonport, following processes regulated by the Office for Nuclear Regulation. The used fuel will be removed, loaded into a qualified transport container and transported to Sellafield prior to long-term storage in the Geological Disposal Facility. Submarines will be dismantled after the fuel has been removed. Work is underway to prepare the dock facilities and associated resources in line with plans to recommence defueling in 2026.

Dismantling of Swiftsure commenced in Rosyth in 2023. This demonstrator project will refine the disposal process and is on track to be dismantled by the end of 2026, achieving the commitment given to the Public Accounts Committee in 2019.  Lessons learned from these defuel and dismantling projects will provide more certainty around the schedule for defueling and dismantling the remaining 22 decommissioned submarines.