"There are so many things you can do with an extra day," enthuses the 36-year-old brewer, inspecting barrels of beer.

The north London brewery where he works, Pressure Drop, will participate in a giant test from June, involving 3,000 employees in sixty companies, working a four-day week.

This trial, touted as the largest in the world ever conducted, aims to help companies shorten their working hours without lowering wages or slowing down their activity.

Similar trials have taken place in Spain, Iceland, the United States and Canada, and should start in August in Australia or New Zealand.

Alex Soojung-Kim Pang, program director at 4 Day Week Global, which organizes the trials, says the six-month UK test will have the benefit of giving companies more time to experiment and gather data.

Adaptation should be easier for SMEs, which can implement big changes more quickly, he told AFP.

Pressure Drop aims to improve employee well-being, while helping to reduce the company's carbon footprint.

The Royal Biological Society, which is also taking part in the trial, says it wants to give employees "more autonomy".

Like Pressure Drop, she hopes that a shorter working week could attract new employees and especially help retain the best, in a particularly tight labor market in the United Kingdom.

At 3.7%, the unemployment rate is the lowest in almost 50 years and job vacancies, which reached a record at 1.3 million.

not so pink

Brewery founder Sam Smith admits staying closed for three days a week would pose challenges as 'we need to be open all the time, but that's what we're going to study during the trial' .

He plans to give different days off to employees and make two shifts to allow continuous operation.

A worker checks a beer brewing vat at the Pressure Drop brewery in north London on May 21, 2022. Pressure Drop workers are taking part in a giant four-day weekday work test, for six months, involving 3,000 employees in sixty companies in the United Kingdom Justin TALLIS AFP

A shorter working week is easier to implement in the service sector which accounts for 80% of the UK economy.

But for retail, food and beverage, it's more complicated, says Jonathan Boys, an economist at the Personal Development Institute, an association of human resources professionals.

The key to the trial's success, he says, will therefore be to measure productivity, especially in a service economy where much of the work is less quantifiable than the output of a factory.

"If you go from five days to four, you lose a day of work, and therefore production. So the real question is: (...) will an increase in productivity compensate for this day who was lost? (...) If not, then it will be very difficult for us to maintain the four-day week without sacrificing growth".

But for Aidan Harper, co-author of a book that promotes four-day working hours ("The Case for a Four Day Week"), countries that work less tend to have higher productivity.

"Denmark, Sweden, the Netherlands work less than the UK and have high levels of productivity," he told AFP.

Conversely, he adds that Greece is one of the countries in Europe with the longest working hours for low productivity.

For Phil McParlane, founder of recruitment firm 4dayweek.io, a shorter workweek is a winning option for companies and employees alike.

He even speaks of a “hiring superpower”.

Its recruitment firm specializing in flexible working and four-day-a-week jobs, says the number of companies wanting to hire through its platform has quadrupled in the past two years, reflecting the rise of hybrid working and the quest for a better quality of life after two years of pandemic.

© 2022 AFP