The new Chancellor George Osborne has called for a public debate about where reductions in spending might be made. Criticising the secrecy with which the former government made its decisions, he has announced that he is open to suggestions from all quarters about where the axe might fall.

Here, then, is one suggestion. There is an obvious way of saving at least pound;1 billion in education that no politician has dared to mention - challenging the glaring anomaly of sixth-form funding.

Now that times are really tight, could Education Secretary Michael Gove be the one to bite the bullet?

The anomaly is easily stated. Children in primary schools are taught on average in classes of about 27 pupils. In secondary schools, group sizes fall, but for the first five years are still well above 20 pupils. In higher education, the average group size is larger still. But for the two years that we call the sixth form, the number drops to an average of 11. A moment’s reflection will underline what an extraordinary arrangement this is.

How can it be that for the first few years at school, a class size of almost 30 children is acceptable and yet, after 10 years in the system, pupils need to be taught in groups of less than half that size? How can it be that the very pupils who have done best in classes of more than 20 in the lower school suddenly need to be cosseted in much smaller groups? And how can it be that those being prepared in the main for higher education should take a step back from, rather than towards, the teaching arrangements they will encounter there?

The answer cannot be educational and must be historical. Decades ago, very few pupils remained in education after the age of 16, so the cost of teaching them in very small groups would have been minimal. In recent years more have stayed on, but the numbers in many schools still fall well short of the cohort size needed to maintain both the subject choice we deem necessary and a level of efficiency comparable with other stages. Plans to open yet more sixth forms at a time of falling rolls is certain to exacerbate the problem.

The solution is clear, however. Large further education and sixth-form colleges can and do recruit young people in sufficient numbers to combine efficiency with effectiveness and choice. Moreover, their results demonstrate that increased size is associated with an increase in performance rather than, as some might fear, the contrary.

It is argued that keeping sixth forms in schools increases participation rates post-16. In fact, the opposite is the case for those young people we find it hardest to retain. It is said that having a sixth form attracts the best teachers since they prefer to teach sixth-form groups. This may be true, but we have surely stopped organising our public services for the benefit of the staff rather than the client or taxpayer.

None of these arguments holds water compared with the simple arithmetic. The Young People’s Learning Agency currently spends some pound;2bn per year on school sixth forms. If we ran them at the level of efficiency of a primary school, we could save at least half of it. There are more savings to be made in comparable areas in the FE sector, and it could be done without damage to results. What are we waiting for?

Mick Fletcher, Education consultant.