I’m not sure how I obtained it, but it is an example of one of those “underground” documents which circulate in organisations among disaffected staff. Managers would doubtless disapprove of them: indeed, some employment tribunal cases have involved such documents being cited as evidence of disloyalty and of bringing the organisation into disrepute. However, in situations where morale is low and trust in management has all but disappeared, they can serve an important therapeutic function by promoting a sense of solidarity among colleagues.

One item on my list is clearly designed for a meeting where someone has made a fatuous contribution: “Thank you - we’re refreshed and challenged by your unique point of view.” An annoyingly persistent person might provoke the question: “If I throw a stick, will you leave?” If this is not well received, add: “Do I look like a people person?”

Many of us will have attended “staff development” events where we might have been tempted to observe: “It sounds like English, but I can’t understand a word you’re saying.” Drifting into total fantasy: “I’m already visualising the duct tape over your mouth.”

Let me offer a final example from my list before I consign it to the shredder. “Errors have been made - others will be blamed.” Back-covering when things go wrong is commonplace in large organisations. Some senior managers are expert at ensuring their survival, whatever the circumstances. Shifting responsibility onto someone less senior, who may not be in a position to set the record straight, is an option.

Of course, most of the time we stop short of making such remarks and, in the context of teaching, there are good reasons for this. Apart from considerations of social courtesy and the need to find ways of working with people we may not like, the values represented by the educational system would sit uncomfortably alongside a climate in which rudeness and sarcasm became the norm.

Teachers are expected to set an example in terms of showing respect for pupils and for each other. Accounts of proper professional conduct emphasise such qualities as fairness, civility and empathy. That is not to say there is no place for light banter between colleagues who know each other, but care has to be taken not to stray beyond acceptable boundaries.

However, in certain situations, the conventions of professional behaviour may prevent a serious problem being addressed. Where the leadership has lost the confidence of staff and the climate is affecting staff and pupils in negative ways, there comes a point when plain speaking is required. Tact and diplomacy only take you so far.

I sometimes say that “niceness is not enough”, by which I mean there are occasions when people may have to be told what they don’t want to hear. But if we are willing to dish out criticism, we have to be prepared to be on the receiving end as well.

Walter Humes is research professor of education at the University of the West of Scotland.