Senior managers have overtaken teachers at the top of the unpaid overtime league table, the TUC has said.
People should take their breaks, says the TUC
The union group said its research showed overworked managers could earn another £24,000 per year if they were paid for the overtime they put in.
Teachers also burned the midnight oil, working on average 11 hours 36 minutes each week without pay.
The TUC is encouraging people to work only their proper hours on Friday as part of its labour campaign.
And it says they should take their proper breaks.
The research suggested workers in other areas such as law, finance and accountancy also suffered from the long hours culture.
Employees in the UK still work the longest hours in Europe, the organisation said.
However, the figures show the number of people who work unpaid overtime has fallen for the fourth year in a row.
According to the figures from the TUC, 4.76 million workers did unpaid overtime last year, which is a 6% fall since 2001.
TUC leader Brendan Barber said the aim of the campaign was to encourage people to think seriously about their own work life balance.
He said: "Work Your Proper Hours Day is an opportunity for a bit of fun after work and during lunch breaks up and down the country.
"But it should also make us all think seriously not just about our own work-life balance, but also about whether we can organise our workplaces better so that we can be just as productive but get home a bit earlier.
"We are beginning to cut the UK's working hours, but there is still a long way to go before the UK gets anywhere near the European average."