Days, weeks, or even months after you have posted the application, a letter arrives inviting you to an interview. Seldom do you have more than 10 days’ notice, so all that preparation you thought unnecessary becomes urgent. It is not unheard of to be phoned 24 hours before an interview.

You may take the opportunity to visit the school. This cuts two ways. If the school is attractive and the sort of place you might want to work, you may lose sleep over your preparations. On the other hand, crumbling walls, terylene-clad staff and dog-eared book cupboards are not the best thing for morale. You will also have a chance to assess the quality of the opposition - the other candidates. They could be shiny bright aspiring achievers, or a bunch of duds. Either can be a blow to your ego.

When the big day comes and you reach the school, assuming you can find it, you’ll want to be directed to the toilet and a waiting room. You might have to sit with the naughty kids, waiting to see management - and find they are more relaxed than you are.

Or perhaps a busy office is full of people who want to be nice to you and make you feel better. But you want to rehearse your answers and do your breathing exercises in an empty staffroom.

Wherever you sit, there is little chance you will be taken at the appointed time. It is unnerving to be taken early, because someone else has realised it is not worth coming. Worse is to be kept waiting for half an hour. Maybe they are asking big questions - or expecting very long answers.

The less officious and more friendly and inane the greeting, the better. You know they’re scrutinising you closely. But it is easier to stop the sweating, shaking and stuttering if they kid on they are nice people.

The interview room may be a senior management office with an array of year planners, under-used computing equipment and oddly shaped trophies. Or it can be an empty room in council buildings.

Seating configurations vary. The fashionable believe that low chairs, arranged in the round, encourage informality. Most candidates will find it has the opposite effect. You sit, knees to chest, sunk in the foam rubber of seventies furniture, trying to retain some dignity. Then you find you cannot make eye-contact with anyone in the room.

You will feel most comfortable seated at a wide table opposite the members of the panel. The protection offered by the table provides a measure of comfort. It may seem confrontational, but why kid on that it isn’t? You can also see when members of the panel yawn or look at the wall clock.

Some panels notify you in advance about possible topics. Some give you the chance to make a short presentation, leading to questions. Either of these is good. More common, and more of a problem, is to have no idea about what questions are going to come up. In this situation, some panels give you the benefit of the doubt and reword questions or ask supplementaries. Other panels sit and stare at you blankly. This is seldom helpful.

Your responses can vary. Once or twice you will, inexplicably, do well. You are asked manageable questions, which you answer.

Sometimes one question will blow it for you, because it’s on something you’ve not thought about, or something you have never heard of. At this point you want to stop wasting time and excuse yourself, rather than giving a lengthy and evasive answer while your examiners write “fail” in the appropriate box.

In most cases you get the results on the day of interview, but if your interview is on Friday you can wait a weekend.

Nowadays interviews for long-term or permanent posts are put off for as long as possible, and an interview can be held on the last day of term. As a supply teacher, you can feel sorely disappointed to be told at 5 o’clock the day before the holidays that you will be unemployed in the new term.

News of the interview will come in a phone call. The successful candidate has little to worry about. The unsuccessful candidate will usually hear a terse voice at the end of the phone, giving an assessment that is little more than useless. “Close second” and “strong leet” are stock phrases, as the chair of the panel obscures an awkward situation with some face saving flannel.

Ultimately, only the following things are true: The composition of interview panels is as varied as the personalities and abilities of the interviewees. You can never know how your performance compared with that of the other candidates, and you can never know how office politics contributed to the decision making. The only thing to do is your best, in the hope that the system, quirky though it is, will come to a suitable decision some of the time.