Teachers work more unpaid overtime than nearly anyone else in the country and the situation is getting worse, research published reveals today.

More than 729,000 teachers and education professionals routinely work unpaid overtime at an average of 12.1 hours a week, according to the new analysis of government statistics by the Trades Union Congress (TUC).

Only chief executives work harder with an average of 13.2 hours a week unpaid overtime on average.

The study also reveals that more than half (51.8 per cent) the teaching profession is working excessive hours for free – a higher proportion than any other occupational group except financial institution managers which had 57.7 per cent.

And the situation is getting worse for teachers. The previous year in 2015 there were 723,000 who worked an average of 11.9 hours unpaid overtime each week.

The trend suggests that any attempts that are being made to reduce workload pressures on teachers are not having an impact, unions claim.

Kevin Courtney, general secretary of the NUT teaching union, said: “This situation is untenable. Long and unmanageable working hours are the biggest single reason cited by teachers for leaving the profession.”

He added: “It is the Government's obsession with continual change alongside punitive accountability and assessment measures which has created this problem.”

The trend is part of a wider picture of workers across the UK doing far more than they are actually paid for. More than 5.3 million people put in an average of 7.7 hours a week in unpaid overtime in 2016, which came to 2.1 billion hours of unpaid overtime in total – equating to free labour worth £33.6bn.

TUC general secretary Frances O’Grady commented: “Few of us mind putting in some extra time when it’s needed. But if it happens all the time and gets taken for granted, that’s a problem. So make a stand today, take your full lunch break and go home on time.”

The Department for Education was contacted for comment.