The number of people working more than 48 hours a week has increased by 15 per cent in five years, according to analysis from the TUC.
More than 3.4m (3,417,000) employees now work “excessive hours”, up by 453,000 since 2010.
This resurgence follows decades where the number of people working longer than their official hours actually fell. Historic data from the TUC shows that in 1998, 17 per cent of the working population (3.9m people) were working long-hours, with this percentage dropping to 12 per cent (3m) by 2010. Despite a growth in employment, 13 per cent of the population now work over the Working Time Directive limit of 48-hours a week.
Much of the overtime is unpaid, employees report, and at least one million said they wanted to cut down on their excessive hours.
Recent research from University College London found that people who regularly work extra hours each week were at greater risk of developing heart disease, stress, mental illness, strokes and diabetes.
And this can have a wider impact on colleagues, friends and relatives and puts greater strain on the health service and the benefits system, the TUC said.
Yorkshire and the Humber recorded the greatest rise in collective hours worked, with an extra 30 per cent (279,000) of employees now reportedly working beyond 48 hours per week. An extra 22 per cent of people in Wales clock-up long-hours today compared with five years ago, while the number of people working excessively in London has increased 21 per cent since 2010.
The growth in long hours has affected industries differently, with mining and quarrying seeing the greatest increase, up 64 per cent, in the number of employees working overtime.
Finance and insurance was one of the very few sectors to have seen a reduction, of -3 per cent, in the number of employees working excessively over the last five years.
By law individuals can choose to ‘opt-out’ of the 48-hour working limit, but the TUC said existing rules around working time limits needed to go further.
“We need stronger rules around excessive working, not an opt-out of the Working Time Directive,” said Frances O’Grady, general secretary of the TUC.
“David Cameron will not convince people to vote yes in the EU referendum if all he’s offering is ‘burnout Britain’,” she added.
One option could be to remove the opt-out for employees. But Paula Bailey, employment law partner with Howes Percival said removing the individual opt-out would reduce flexibility afforded to both employees and employers.
“I am not aware of many employers that require employees to work in excess of the 48 hour working week on average. Where it does tend to be used by employers it is in cases where they need that flexibility to ensure that they can cope with peaks and troughs in activity or seasonal demand and compensatory rest may then be offered on other occasions,” she said.
“In many instances, employees themselves wish to do voluntary overtime and/or to take second jobs, resulting in them working in excess of the 48 hours a week on average.
“Removing the individual opt out would not allow employees to voluntarily do this and would reduce the flexibility open to employers,” she added.
Stephen Ratcliffe, employment partner at law firm Baker and McKenzie, said: “It would be extremely interesting to see how enforcement would work in practice if the opt-out were removed. This is especially true in relation to remote and agile working, where it is somewhat difficult for employers to accurately track working time (though they remain technically obliged to).
Ratcliffe said it was also important to remember that the 48-hour maximum is on average over 17 weeks, rather than absolute limit in each week. “The removal of the opt-out may therefore have the unintended consequence that employees who continue to work long hours are forced to take several hours or days off at the end of the reference period for which, depending on the terms of their contracts, they may or may not be paid.