Stress, anxiety and depression are undermining productivity at small businesses with a quarter of staff describing their mental health as moderate or poor, according to data released by the Chartered Institute for Personnel and Development (CIPD).

The CIPD's research revealed that 56% of employees with poor mental health say they have taken time off sick and more than 90% said it negatively affects their performance on the job.

Of the 2,000 employees surveyed, only a third of workers say their organisation supports people with mental health problems well.

"The survey findings provide compelling evidence for why employers need to become more proactive in how they manage mental health at work. Common mental health problems such as stress, anxiety and depression are one of the main causes of time lost to ill health," said Ben Willmott of the CIPD.