At the Cranfield School of Management, for example, the module includes colour consultancy and hot tips on dress and grooming from Kate Dixey, a costume designer.

Dixey says many chief executives are “highly observant” of the way people dress. “If your trousers are too long, your suit shiny and out-of-date, your shirt the wrong fit and poor quality, your dress the wrong shape, they tend to think your mind will be out-of-date as well.”

Dr Jacquie Drake, director of the Praxis Centre for Developing Managerial Effectiveness at Cranfield, believes the same rules apply for teachers asother professionals. Though the code of dress may not be as rigid as for a City trader or lawyer, she believes teachers who look well turned-out, fit and healthy are more likely to command respect and support.

Headteacher Eric Spear says he believes many heads look favourably on teachers who dress like “smart professionals”. “The way you dress and present yourself is a statement about what you feel for the people and pupils you are dealing with.

“In my school the children wear uniform and I expect my teachers to match this with a good standard of dress. No jeans, a collar and tie, nothing casual.”

Drake says: “You can inspire confidence in others by the way you look. If you are well-groomed and healthy you are much more likely to be calm and confident - not hyped up or sloppy but in a state of alert relaxation.

“If you are sensitive to what’s happening inside yourself, if you take care of yourself, then others will feel you are a safe pair of hands.

“You will give people a sense of security as well as a sense of excitement. If you look harassed, exhausted and badly turned-out, you will have the opposite effect. People feel that someone who is sloppy in appearance is also sloppy in work.

“Teachers have to command respect, not only with pupils and fellow teachers, but the community as well. I think their reputation suffers from the fact they don’t look as good as they could.”

She also believes that paying attention to eating a balanced diet, taking plenty of exercise, keeping up with health checks and trying to get enough sleep can also have a radical effect on energy levels.

“If you are in charge of yourself and take care of your whole person, then you are much more likely to be able to work to your full stretch and be exceptionally good at your work. It’s not just a question of putting on a smart suit, it’s a whole way of being.”

Teachers who work into the night and neglect their personal lives are not doing themselves favours in work, says Drake.

“Having a good life outside of work keeps you lively in work. It’s part of a cycle of effectiveness.”