All 17 companies that took part in the latest UK trial of a four-day working week have opted to continue with the model or a variation of it, after seeing benefits in staff wellbeing, mental health and productivity.
The six-month trial, organised by the 4 Day Week Foundation and monitored by researchers at Boston College in the US, involved nearly 1,000 employees across a diverse range of organisations — from housing associations and professional bodies to sports associations and student unions.
Under the trial, participating businesses reduced employees’ working hours without reducing their pay. After the pilot concluded, 12 companies adopted a permanent four-day week, while five chose to move to a “nine-day fortnight” — essentially every other Friday off.
Among the organisations that have made the shift permanent is Bron Afon Community Housing, which employs over 400 staff. Chief executive Alan Brunt said the move has been a success, with no drop in performance or customer satisfaction. “We’ve closely monitored our performance and customer satisfaction. We’re happy with the results so far and will continue to make sure we’re delivering for our customers,” he said.
Other participants included the British Society for Immunology, the National Union of Students, and the Scottish Sports Association. Company sizes ranged from under five employees to over 400, with the most common being small businesses with 1–25 staff.
The trial’s outcomes echoed previous findings from the four-day week movement. According to the 4 Day Week Foundation, 62% of workers reported experiencing burnout less frequently, 41% said their mental health improved, and 45% reported being more satisfied with life.
Joe Ryle, campaign director at the 4 Day Week Foundation, said: “With greater knowledge, expertise and experience of what it takes to successfully implement a four-day week, we’re really pleased to see such a high success rate. People are happier, businesses are thriving, and there’s no turning back.”
To date, the Foundation has accredited more than 235 UK companies that have moved permanently to a four-day week without cutting salaries, representing over 6,000 workers.
While the previous Conservative government dismissed the idea as “part-time work for full-time pay”, the Labour government has shown signs of being more receptive. Deputy Prime Minister Angela Rayner has said a four-day week is “no threat to the economy”, though the policy is not currently included in the upcoming Employment Rights Bill.
Still, advocates argue that momentum is building and public interest is growing. Businesses point to improvements in recruitment, retention and morale as further reasons for embracing the change.
With growing adoption across sectors, the four-day working week may soon move from experimental to expected — especially as more firms seek to enhance productivity while boosting work-life balance.
