The trials of four-day working has drawn interest from economists and businesses keen to find a solution to a slowdown in productivity growth in Britain
Two workers glide between a computer screen and a stainless steel vat making face cream, a scientist in a white coat mixes a formula and a colleague sticks labels on bottles.
Apart from the whir of machines, there is silence: this is "deep work time" at British skincare maker Five Squirrels when staff strive to boost productivity so they can take Fridays off and still get a full week's pay.
Owner Gary Conroy said his 15 workers had smashed through their targets since switching to the shorter week last June and introducing four-hour periods each day when they ignore emails, don't answer phone calls and turn off instant messaging.
What may seem an eccentric experiment is one of a number of trials of four-day working that has drawn interest from economists and businesses keen to find a solution to a slowdown in productivity growth in Britain and other Western economies.
Productivity - or economic output per hour worked - grew at an average of just over 2% a year in Britain from the 1970s until the run-up to the financial crisis, underpinning a steady rise in living standards.
But between 2010 and 2019, it averaged just 0.75% and the Bank of England forecasts it will remain weak over the next few years, partly due to more red tape since Brexit.
In that context, cramming the same output into a four-day week represents the equivalent of a decade's worth of productivity gains before the mid 2000s slowdown - and in the case of Five Squirrels, there's a happier workforce too.
"Everyone was pounding through their work from Monday to Thursday to make sure that Friday, it was definitely going to happen," said production executive Lilly Ellis, 21. "It was really easy to keep that energy up as well. It's not really dropped off."
The company based in Hove on Britain's south coast was one of 61 firms - most with 25 or fewer employees - to take part in the world's biggest four-day week trial last year. Pleased with the outcome, 56 have stuck with the policy.
The vast majority said overall productivity and performance were maintained, though for some firms the need to work longer hours on the four working days meant they failed to cut a full eight hours from the week.
The organisations behind the trial, the 4 Day Week Campaign and research group Autonomy, told Reuters they would be running a new trial from June 12 and had received hundreds of enquiries.
Part of Britain's long-term productivity problem stems from low investment, which was the weakest in the Group of Seven rich nations in 2021, according to World Bank data.
The experience of some companies in the first trial suggests that moving to a four-day week might help, if it prompts firms to spend more on equipment and training.
Stellar Asset Management's chief operating officer Daryl Hine said the financial services firm introduced new technology to streamline and automate processes when it moved to four days.
While that might have led to fears about job losses in the past, Hine said "everybody could see the tangible benefits".
The productivity gains at Five Squirrels were also helped by investment. Conroy bought new machinery to make smaller batches of sunscreen, anti-wrinkle washes and skin-firming serum in a less labour-intensive way, and a new labelling machine.
The company created a weekly schedule too, clustering tasks instead of switching between them, that led to a bottle labelling rate of 120 per hour, up from 25 previously.
Britain is suffering from an acute shortage of workers and larger companies have typically had an advantage when it comes to hiring, but some experts say moving to a four-day week could turn the tables.
