Almost £5,000 of overtime goes unpaid every year, according to new research.
A TUC survey has found that the UK workers do an average of £4,800 of unpaid overtime every year, constituting seven hours and six minutes extra every week.
The problem is most apparent in the north east of England, with unpaid overtime in the region reaching seven hours and 42 minutes.
But staff in Scotland stay on for over an hour less – six hours and 30 minutes in total.
Reacting to its findings, the TUC urged employers to take greater care of their workforce by holding thank you lunches or post-work socials.
"We do not want to turn Britain into a nation of clock-watchers and few mind putting in extra effort from time to time when it is needed, but it is too easy for extra time to get taken for granted and then expected every week," said the TUC's general secretary Brendan Barber.
The combined total of unpaid overtime contributed to the economy worked out at £23 billion, the report revealed.