In the survey of 2,000 workers across the UK, free hours were found to translate into savings of £6,635 for companies. Across the working population, this equates to a total of £142 billion of free productivity for UK bosses.
Within the last 12 months, not only have seven out of 10 workers given their bosses an extra 10 hours of free labour, but 55% of employees have missed a vital family celebration such as a child's or partner's birthday, a child's school play or a family holiday due to a work commitment, the survey found.
It also showed one in 10 male workers has even missed the birth of their child due to a work commitment.
When it comes to the biggest 'workaholics' across the UK, Londoners take the crown, giving their bosses a generous contribution of an extra 12 hours a week. Workers from Liverpool come in second (11.5 hours) and Birmingham workers take third (10 hours).
Other key findings revealed 66% of UK workers experience soaring stress levels on a regular basis and 33% find it difficult to get through the average working week.
Psychologist Corinne Sweet said: "This research is certainly a wake-up call for us to switch off our gadgets and get away from the clutter, pressure and stress of working life.
"Cramming extra work into an already busy working week shows danger signs of us becoming a nation of workaholics, heading for serious psychological and physical 'burnout'."
