Office for National Statistics labour market data analysed by the TUC found 3,337,000 employees were now working more than 48 hours a week, a rise of 250,000 since 2001.
Mental health charity Mind said poor work-life balance could lead to poor mental health in the workplace, which costs the UK economy up to £100bn per year.
Statistics by the ONS show output per hour worked in the UK is 15.9% below the average for the rest of the G7 advanced economies (Canada, France, Germany, Italy, Japan and the United States).
Could a shorter working week actually improve productivity and workplace mental health?
In a recent article for the BBC Gemma Godfrey, chief executive of investment management company Moola, says: “Workers in Germany, for example, could actually stop working on a Thursday and yet still produce more than we do.
“So, therefore, greater and longer working hours doesn’t necessarily mean that we’re more productive, especially when it negatively impacts our health and our ability to do our job.”
But, she says, the solution involves caring for employees’ overall wellbeing, not simply cutting hours.
She says: “How are we looking after them? Are we also looking at lifestyle benefits, harnessing modern technology to be able to offer greater flexibility as well as making sure we still deliver?
“That’s what’s going to drive profits and the economy.”