Workers in the North West are being urged to take a lunch break and leave on time.
New figures show they did nearly three million pounds worth of unpaid overtime last year.
The TUC says almost half a million people here put in an average of 7.6 hours a week in unpaid overtime during 2017.
This averages £5,897 a year that each of those workers is losing out in pay.
The union is calling on bosses to move away from a long hours culture.