Of the 26.8 million working days lost due to work-related ill health in 2017/18, 57% - 15.4m - were due to work-related stress, depression or anxiety, according to the HSE's annual injury and ill health statistics (13-page / 325KB PDF).
The report revealed that 595,000 workers suffer from work-related stress, depression or anxiety, and that 239,000 workers experienced a new case of such mental illness in 2017/18.
People working in the education, human health and social work, public administration and defence sectors are more likely to experience higher than average rates of stress, depression or anxiety, according to the report.
Regulatory compliance expert Laura Gillespie of Pinsent Masons, the law firm behind Out-Law.com, said the statistics show that mental health is a serious issue in the workplace.
"Traditionally, many employers have focussed on managing physical health and safety but legal duties concerning health and safety are not limited in that way," Gillespie said. "The Health and Safety at Work Act 1974 clearly requires employers to ensure the 'welfare' of their employees, so far as reasonably practicable, when at work."
"Employers should recognise the risk that work-related stress can pose. Putting in place support mechanisms and creating a culture where employees feel able to share challenges with mental health should enable employers to identify risks and put strategies in place to manage those," she said.
Pinsent Masons recently signed the Mindful Business Charter, a charter it jointly developed, that commits signatories to promote a culture of openness about mental wellbeing and to a series of other principles centred on improved communication, respect for rest periods and considerate delegation of tasks, among other things.
Pinsent Masons also recently published a whitepaper focussing on mental health to mark World Mental Health Day. It is focused on the higher education sector and features articles on the growing student mental health problem, the legal implications of caring for students and the issues to consider when dealing with staff stress.
The HSE report also provided an insight into the workplace safety.
There were 144 people killed at work in 2017/18 and a further 555,000 "non-fatal injuries" to workers, according to the report. However, health and safety law specialist Kevin Bridges of Pinsent Masons said the statistics only detail part of the picture.
"It is striking that the number of workplace deaths remains at a similar level having plateaued around the 140 per year mark in 2012/13," Bridges said. "What this figure hides, however, is the number of non-workers killed associated with work activities as well as occupational road-related deaths, which pushes up the numbers significantly."
"Even more striking perhaps is the figure of 12,000 lung disease deaths each year estimated to be linked to past exposures at work. It is essential, therefore, that employers recognise the need to channel resource in to managing not only people’s safety, which is more tangible, but also their health, as well as their welfare and well-being," he said.
The annual financial and human costs of work-related injury and new cases of ill health in 2016/17, excluding long latency illness such as cancer, was estimated to be £15 billion. More than a third of this - £5.2bn - can be attributed to workplace injury, according to the HSE report.
"Financial costs cover loss of output, healthcare costs and other payments made," it said. "Human costs are the monetary valuation given to pain, grief, suffering and loss of life."
The report also revealed that there were 493 cases that HSE either prosecuted or referred to the Crown Office and Procurator Fiscal Service (COPFS) for prosecution in Scotland where a conviction was achieved in 2017/18. HSE and COPFS served fines totalling £72.6m against those they successfully prosecuted in 2017/18.