Select committee: Public Accounts Committee
Conclusion 13
28th Report - Decommissioning Sellafield
Published 4 Jun 2025
Addressed to HM Treasury
Public Accounts Committee Decommissioning Sellafield All items in this report Report on parliament.uk ↗ Inquiry on parliament.uk ↗
Conclusion (the committee's words)
When it last took evidence on Sellafield, the previous Committee was told that major project delivery was improving.32 The NDA told it that “cost forecasting is improving” while the Department said that “for the first time now, the estimates of those costs have begun to stabilise”.33 Even then though, the nine major projects underway were, between them, delayed by 165 months and expected to cost £913 million more than originally budgeted.34 However costs, and delays, have risen considerably since then for the four projects which were two years or more away from completion. These four projects are now expected to cost £1.15 billion more between them than when the previous Committee reported, while each will be delayed by between 58 and 129 months. Sellafield Ltd accepted that £546 million of this cost increase was caused by poor planning and poor contractor performance. It attributed £191 million to delays resulting from the COVID–19 pandemic and higher–than–forecast inflation.35
From: Public Accounts Committee, 28th Report - Decommissioning Sellafield (HC 363), 4 June 2025
Government response
Latest Treasury Minutes progress report to the Committee of Public Accounts on the Twenty-eighth Report of Session 2024-26
The government responded to the whole report on 4 June 2026 (deadline 4 August 2025).
Treasury minutes: Government response to the Committee of Public Accounts on the Twenty-eighth report from Session 2024-26
Published 18 September 2025.
Summary written by Accountability Index from the government's response. It is not the government's own words.The government says it agrees with each of the Committee's recommendations covered in this extract, with target implementation dates ranging from December 2025 to March 2027, though some are already implemented and some publication details remain to be settled.
- On oversight (recommendation 1), the government agrees and describes the recommendation as implemented. Since January 2025 the department's Principal Sponsor chairs monthly performance meetings, and a review of the revised governance structure will be initiated within 2025-26.
- On medium-term targets (recommendation 2), the government agrees, with a target date of March 2027. Work "is required to establish how and then when this information would be made public", and DESNZ will commission an independent, externally led review of the NDA Group by end-2025.
- On asset management (recommendation 4), the government agrees and says the recommendation is implemented. It states that "Solely increasing the productivity of maintenance teams misses the demands" of the site's complex asset picture.
- On long-term cost scenarios (recommendation 5), the government agrees, with a target date of December 2026. It says "It will be necessary to agree the mechanism and timing, including what is published".