Why are we so obsessed with exams in this country? With the recent introduction of new qualifications at 17, pupils in England and Wales now sit public examinations at ages seven, 11, 14, 16, 17 and 18. No other country puts its children through so many.

Until the National Curriculum was first established, we made do with the relatively frugal diet of GCSEs at 16 and A-levels at 18. Since then, politicians have fallen in love with them. While interest rates have been used to control the economy, externally set public examinations have been used to control, monitor and enhance the performance of schools.

The line is that exams can be used to measure the achievements of both pupils and teachers, and in doing so will improve education.

But do we really need so many? And who is counting the cost? It is too early to assess the educational benefits of the latest addition to the fold, Curriculum 2000, but the effect on the budget can be counted.

In my sixth-form college, the amount spent on examinations has gone up 70 per cent in the past year. We (or, more accurately, the taxpayers) now spend 50 per cent more on exams than on books, materials and classroom equipment.

Now, 5 per cent of our total grant from the Further Education Funding Council for running courses is spent on furnishing our students with certificates.

It’s not just exam fees, either. We have yet to consider the days of teaching lost while students revise (more than half a term in the case of GCSE exams), nor the hours lost while students sit in exam halls. When re-sits of modules are taken into account, I estimate that an average A-level student will spend about 30 hours in the exam hall, doing papers which will have cost about pound;300 in fees. You could afford to pay teachers in our college around pound;3,000 per year more if external examinations were abolished.

This may seem a radical suggestion, but which is more important to the quality of education, a system of qualifications or a well paid, well qualified teaching profesion backed up by well resourced classrooms?

The plethora of external assessment not only drains schools of valuable resources, but also undermines the status and authority of teachers. We are no longer deemed competent to assess our own pupils.

Our job is now to ensure our students pass external tests. The emphasis on results and outcomes stifles imaginative teaching. In preparing lessons, aims and objectives and syllabus coverage take precedence over taking risks, or improvisation. We no longer choose a syllabus on the basis of whether it will interest or inspire out students - we select it on the grounds that it will be easier for them to get their grades. After all, if our students fail, we fail.

At a recent parents’ evening, I was berated for not allowing a student to repeat their coursework because they had made a mess of it. This was apparently my fault, as I had not told her how to do it the first time. I had failed in my duty to win her success in the exams game.

Education is no longer assumed to be done in the classroom - it has to be seen to be done. All achievements have to be certificated. In-service education of teachers reflects this priority: we spend more time mastering the intricacies of assessment systems than considering how we might teach our subjects better.

And what is the effect on children? Although most are resilient, many find the pressures of all this external testing hard to cope with. It is one thing to find out you are a failure at 16 - now they are thinking about assessing four-year-oldsI I am not against examinations. In fact, I am a principal examiner who sets A-level papers. The examination boards do a thorough and valuable job in providing national exams that are as robust and fair as possible. They even export this expertise abroad.

But you can have too much of a good thing: we need to review the unhealthy reliance we place on large-scale external exams and consider the cost-effectiveness of the money we are spending on them.

Chris Little teaches at St Vincent sixth-form college in Gosport, Hampshire, and is a principal examiner in A-level maths for the exam board, OCR