More than 3,000 workers at 70 companies are set to begin a six-month trial of a four-day working week with no loss of pay.
Organisers of the scheme say it is the biggest four-day week pilot programme in the world.
Companies signed up to the trial will pay staff the same wages for 80 per cent of their hours, in exchange for a commitment to maintain at least 100 per cent productivity.
The 4 Day Week Global group is organising the trial in partnership with the Autonomy think tank, the 4 Day Week UK Campaign, and researchers at the universities of Cambridge and Oxford, and Boston College.
Companies taking part provide products and services ranging from education to workplace consultancy; banking; care; financial services; IT software training; professional development and legal training; housing; automotive supply services; online retail; sustainable home care; skin care; animation studios; building recruitment services; food and beverage and hospitality; digital marketing; and case management for people recovering from traumatic injury.
UK salary guide 2022: how much should you be earning?
Researchers will work with each organisation to measure the effects on productivity and the well-being of its workers, and on the environment and gender equality.
“The UK is at the crest of a wave of global momentum behind the four-day week," said Joe O’Connor, chief executive of 4 Day Week Global.
“As we emerge from the pandemic, more and more companies are recognising that the new frontier for competition is quality of life, and that reduced-hour, output-focused working is the vehicle to give them a competitive edge.
“The impact of the ‘great resignation’ is now proving that workers from a diverse range of industries can produce better outcomes while working shorter and smarter.”
Top 20 cities in the world with best work-life balance - in pictures
“We’ll be analysing how employees respond to having an extra day off in terms of stress and burnout, job and life satisfaction, health, sleep, energy use, travel and many other aspects of life," said Juliet Schor, professor of sociology at Boston College and lead researcher on the pilot.
“The four-day week is generally considered to be a triple-dividend policy, helping employees, companies and the climate. Our research efforts will be digging into all of this.”
Ed Siegel, chief executive of Charity Bank, which is taking part in the trial, said: “We have long been a champion of flexible working but the pandemic really moved the goalposts in this regard.
"For Charity Bank, the move to a four-day week seems a natural next step. The 20th-century concept of a five-day working week is no longer the best fit for 21st-century business.
“We firmly believe that a four-day week with no change to salary or benefits will create a happier workforce and will have an equally positive impact on business productivity, customer experience and our social mission.”