According to the charity's Mental Health at Work Report 2016, 49% of line mangers would find even basic training in common mental health problems useful and 38% would appreciate training on how to talk to employees about wellbeing.
The findings are from BiTC's National Employee Mental Wellbeing survey. Participants from front line workers to directors took part via a YouGov panel survey (3,036 respondents) and a public open survey (16,246 respondents).
The YouGov poll revealed that 76% of line managers believe employee wellbeing is their responsibility, yet only 22% of them have received some form of training on mental health at work. Four-fifths said obstacles prevented them from being able to offer support, including not enough time for one-to-one management (26%), having to reach performance targets (22%) and conflicting priorities (21%).
One public survey respondent said: "My manager just did not understand how I felt -- line managers need more training, and they need to stop applying more and more pressure when they are told that someone is at breaking point."
Asked what they would find useful to help them support employee wellbeing, 54% of line managers said information and guidance online and 36% cited employee assistance programmes (EAPs) with a confidential helplines. The same percentage believe a mental health first aid course would help and 33% said counselling or psychotherapy.
While the majority of board members and senior managers (60%) believe their organisations supported people with mental health issues, only 11% of workers said they discussed a recent mental health problem with their line manager. This disparity, the report says, demonstrates a "concerning disconnect[ion] between employees' experience in the workplace and what those running the company believe is taking place".
Asked how well their organisation supported workers with mental health problems, 30% answered "not very well" or "not very well at all".
A line manager who took part in the public survey said of their employer: "The organisation almost sees mental health issues in individuals as a potential disciplinary matter."
The polls found that around one in 10 employees who experienced symptoms of poor mental health faced disciplinary action, including dismissal. "The threat of disciplinary action when experiencing mental ill health is very real," says the report. "This could be a worrying indication of illegal employment practice."
There is also a "pervasive culture of silence that remains entrenched across workplaces", BiTC says. More than a third (35%) of employees affected by mental health problems did not approach anyone for support. A quarter sought help from someone at work.
Half of all employees would not feel comfortable discussing mental health issues at work and the same proportion would not discuss mental health with their line managers.
Despite believing that co-workers care about each other's wellbeing (77% felt that their colleagues were very or fairly considerate), 86% would think twice before offering to help a colleague with a mental health problem.
Some 77% of employees have experienced mental health issues and, for 62% of them, work was a contributing factor. Eleven per cent of employees felt their mental health was either "poor" or "very poor" at the time of taking the survey.
Peter Simpson, chair of business in the Community's wellbeing leadership team and CEO of Anglian Water Group, said: "The significant role of line managers and the support they need to do their job well is expressed in clear terms in this survey. So too in the need for clear and decisive leadership to create organisational cultures that drive positive change. These findings are just the beginning. This is a three-year process, with the same questions being asked of employees again over the next two years."
Professor Dame Carol Black, senior policy advisor on work and health to the British government, added: "Employers have a duty of care to respond to their employees' mental health needs in the same way they respond to physical conditions, such as cancer or diabetes.
"We must make training more widely available to the managers who are on the frontline, and we need to intervene early to prevent an escalation of mental health problems. That means learning to recognise the signs and making it easier for people to talk about mental health at work. It is about taking a preventative approach and building resilience across the organisation.
"It is crucial for senior management to show leadership on mental health, with a sustained and visible commitment to change. They must encourage and take part in an open conversation to normalise discussion about mental health in the workplace. I urge all employers to consider how these findings can help improve their own response to workplace mental health and wellbeing."