The UK’s largest nuclear site, Sellafield in Cumbria, may continue leaking radioactive water into the ground until the 2050s, a decade later than previously expected, according to a recent report. The leak stems from the Magnox Swarf Storage Silo (MSSS), described by the Nuclear Decommissioning Authority (NDA) as ‘the most hazardous building in the UK’. The MSSS has been leaking since 2018; the report warned that delays and missed targets in cleaning up the site pose ‘intolerable risks’ and could prolong the danger. It also highlighted cost overruns, slow progress, and cultural issues at Sellafield, urging the Government to treat the situation with greater urgency. Though the NDA claims the leak is contained and not a threat to the public, MPs warn that the site’s condition is a present-day hazard, not a distant concern. Plans for a permanent underground nuclear waste storage facility remain years from completion.