Select committee: Public Accounts Committee
Conclusion 10
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)
Sellafield Ltd has–in conjunction with the NDA and the Office for Nuclear Regulation–set a ‘strategic tolerance’ for completing key activities. It described this to us as the date “we really want to hit”, to ensure that the site is fully cleaned up by 2125. We explored the consequences of not achieving ‘strategic tolerances’ with particular reference to the ‘Waste Vitrification Plant’ and were told that there is no fundamental engineering reason why the ‘strategic tolerance’ of 2039 could not be extended in this case. However doing so would need careful consideration as it could affect planning assumptions made elsewhere on the site (such as those relating to Sellafield’s future requirement for sample analysis capabilities).20 The NDA recognises that devising measures which allow measurement and reporting of progress in the short term, while also providing confidence that Sellafield Ltd will achieve long–term outcomes, is challenging.21 It also told us that Sellafield Ltd was right to be “super–cautious” because of the extremely hazardous nature of its waste – though it was conscious that “this may sound like a load of excuses”.22 We sought to understand how the NDA would identify underperformance – particularly in light of the Office for Nuclear Regulation’s request that the NDA do more to hold Sellafield Ltd to account for delivery, safety and security.23 We note that Sellafield Ltd has not only missed most of its targets for retrieving and ‘vitrifying’ waste in recent years, it has generally fallen well short of the level of performance it deems ‘Acceptable’.24
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".