The question of fun became a hot issue when I was working with a German company some years ago. It was at one of those off-site meetings of senior executives intended to establish the company's underlying values. The desired outcome - nothing too ambitious, of course - was to influence employees' behaviour.

Time was spent discussing a new statement of corporate values. I suggested the board aimed for fewer than seven values, based on the well-tested rule of social psychology that employees can recall somewhere between four and seven such statements.

We reached agreement on four values relatively easily: challenging goals, co-operation, innovation and service. I then suggested that, as the company was full of young information technology specialists, fun might be added to the list.

The ensuing silence was broken by the chairman with a haughtily Calvinistic: "We don't employ people to have fun."

So we settled on integrity instead. Needless to say, the resultant statement of values had very little impact on either the staff or the company.

A glance at this year's popular business literature confirms the extent of what I regard as a potentially worrying problem at the top. There are few references to having fun. There are even fewer acknowledgements that humour is a necessity, especially when tasks are repetitive. Yet the reality is effective leaders use these tools as mechanisms for motivation and catharsis.

And leadership can occur at any level and in an organisation, in a myriad personal variations. Some of the finest exponents of leadership occupy what might be perceived as minor roles: project team leaders, call-centre supervisors or mailroom managers.

What they have in common is an intuitive understanding of effective leadership. They use humour to break potentially monotonous routines, to raise the feel-good factor and, importantly, to maintain morale and efficiency in areas where it is all too easy to have one's enthusiasm sapped. Their methods may vary, but the result is the same. Birthdays, anniversaries, meeting targets, pay days - all are used as excuses for celebrations.

It is not simply about setting goals and driving their team towards them. It is as much about igniting an unpredictable frisson, a collective struggle that enlivens boring tasks.

A good analogy is the Japanese use of physical exercises and singing to counter the effects of increasingly repetitive manufacturing processes.

Too often such leaders are appreciated only when they leave. Suddenly, the standards we took for granted start to fall away. Mail does not arrive on time. The turnover of staff in telesales trebles. Food in the canteen is cold. Data takes a week to be processed. Worst of all, their irreverent sense of the ludicrous and their infectious humour is lost - and along with it the ability to hold a team together.

But if the common link between such stars is the injection of fun into the working environment, it is only recently that the subject of fun has attracted the attention of serious researchers.

As more companies admit that all jobs become boring after a while, a style of leadership is emerging whose primary function is to turn the repetitive and routine into fun - in other words, to admit that work organisations do not offer the endless self-fulfilment that idealists promised in the 1980s.

With precision timing (whoever said the social sciences did not create products?), three North American academics have published their findings on the use of humour among leaders, in the Journal of the American Academy of Management (April 1999).

They surveyed 115 leaders (middle to senior managers of a Canadian financial services firm) and 322 followers, to test the theory that humour is positively associated with individual and unit level performance.

They found the impact of humour varied with different styles of leadership. For example, transformational leaders used humour to positive effect while laissez-faire leaders used it to negative effect.

Leading on from that, they concluded that humour created a positive atmosphere within a unit and thereby stimulated higher levels of collective productivity.

And, finally, rather than describing what employees do as deadly dull, we should recognise that many people like routine work, provided they have control and provided their leaders make it exciting and thereby more rewarding.

John W. Hunt is professor of organisational behaviour at London Business School