Could a four-day working week work across the United Kingdom? A British pilot offers evidence that some employers were willing to continue with shorter hours, but the available account leaves important questions about productivity, wages and public services unresolved. According to a research compilation published by 4dayjob.com, the UK pilot ran from June to December 2022 and involved 61 companies and approximately 2,900 employees. It used the 100-80-100 model: full pay for 80 per cent of normal working time, with the expectation of maintaining full productivity. That distinction matters. The experiment examined reducing working time while protecting pay, rather than simply fitting the same hours into fewer days. Maintaining output was part of the model’s ambition; that alone does not establish that every participating workplace achieved it. The compilation reports that 92 per cent of companies continued with a four-day week after the pilot. This suggests substantial employer interest following practical experience. However, continuation is a different measure from independently demonstrated productivity, and it does not establish that every company made the arrangement permanent. Participants came from sectors including marketing, technology, finance, charities, hospitality, retail, healthcare, manufacturing and professional services. That range makes the experiment relevant beyond technology businesses. Nevertheless, the available account does not give sector-by-sector results or explain how employers maintained staffing and service coverage. It also lists employee wellbeing measures, including burnout and work-life balance, without supplying usable numerical results for those measures in the available text. The scale of any improvement therefore cannot be assessed from this account. The evidence supports a limited but useful conclusion: a shorter week with protected pay proved attractive enough for many participating employers to continue. Whether it could deliver comparable results throughout British workplaces—particularly public services—remains unanswered by the information available here.