Firms are now being urged to use a new test to identify any counter-productive behaviour which can surface in managers at times of stress.

A bad manager can alienate staff

Occupational psychologist Geoff Trickey said firms usually tested managers for their bright side, such as extravagance or enthusiasm, but he warned that even these positive attributes had a negative side.

The new test, developed in the United States, includes a number of measures aimed at discovering whether an enthusiastic person could also be moody, irritable and hard to please, while a careful manager could be difficult to work with if he or she was unwilling to take chances.

A manager described as independent or self-sufficient could be unaware of how their actions affected other people, according to the test.

Another pointer was whether a confident manager was in fact arrogant and blamed mistakes on other people.

Cracking point

Mr Trickey said that everyone had a dark side to their personality and was in danger of `cracking', sometimes by shouting at children or at their staff.

"The very things that can make managers successful can also destroy them," he said at the British Psychological Society's occupational psychology conference.

"Our advice is that when firms are assessing people for a job, they should try to find out about their dark side as well as their bright side."

A questionnaire developed with the help of the new test could help reveal a person's dark side, said Mr Trickey, who works for Kent-based Psychological Consultance Ltd.

The test could show whether a person who appeared charming, friendly and fun-loving was also manipulative and impulsive.