A TUC-led initiative, now in its tenth year, urges workers to work their proper hours today (28 February) - starting and finishing on time and taking allocated breaks away from their work station.
According to TUC statistics, if staff who regularly work unpaid overtime did a year's worth of unpaid hours from the start of the year they would only start earning today.
"This is an astounding statistic," commented CWU general secretary Billy Hayes "which is why we fully support this initiative and encourage all our members to adhere to their agreed start and finish times and take their proper breaks not only today but every day.
"Whilst celebrating the unrewarded hours effectively donated by staff to help employers and boost the UK economy by a staggering £28bn, this light-hearted campaign also highlights the serious effects working additional hours has on workers' well-being and stress levels," explained Billy.
This year's campaign will focus specifically on how the recent recovery in the labour market has affected the number of unpaid hours worked and will also highlight which jobs and regions in the UK do the most unpaid overtime.
The campaign, broken down:
1. What's "Work Your Proper Hours Day"?
Today - February 28 - marks the day when the average UK worker who does unpaid overtime finishes the unpaid days he/she works every year, and starts earning money.
2. So who works for nothing?
The TUC estimates that around one in five of us regularly put in extra time either at the end of the day to "just finish this off" or "get this panic job out the way" during the day, by taking a "working lunch" without leaving our work stations, or arriving before our duty to "make an early start".
3. But that's not a big deal is it?
It might be just half an hour or so each time, but it all mounts up. Research suggests that the amount of unpaid work done by us totalled an incredible £28 billion last year.
4. We're understaffed at our workplace and I don't want to let people down
Actually, it's excessive and regular unpaid hours that lets people down. Around a million new jobs could be created if these understaffed companies simply employed enough people. And long hours are not good for us either - they cause stress, they wreck relationships and they make caring for children or dependents more difficult.
5. But I want my company to succeed
We all want UK companies to succeed. Excessive hours are bad for business too. A tired worker makes mistakes and is more likely to suffer or cause an accident at work. Fatigue also leads to underperformance and is a major factor in many illnesses. Successful companies need healthy, alert, motivated and focussed workers.
For more information visit Work Your Proper Hours Day. http://www.worksmart.org.uk/workyourproperhoursday/" onclick="window.open(this.href);return false;
The healthy option. 
That's news to me. 