One of the most enduring and misguided ideas in education is the belief that large groups of pupils can be taught to their full potential by one person. They can be taught, of course, and taught well with all the boxes ticked for holding interest, explaining clearly, motivating, inspiring even. But class teaching is not the same as giving quality support for the learning needs of each individual pupil. This is something different.
However brilliant a teacher's exposition, or however supportive group learning may be, there will always be pupils who require explanation, discussion and guidance on a one-to-one basis. With class sizes of 25 or 30, token gestures and very brief encounters between teacher and pupil are the most that can be offered at both primary and secondary level.
The maths is clear: a one-hour lesson with 30 pupils offers two minutes per pupil if everyone is working individually for the whole session, one minute per pupil if half the session has involved teaching the class. There is no time for uninterrupted, high quality, individual tuition.
What can be done about this situation? Carry on as normal, do one's best and keep smiling? Keep those snappy, interactive lessons going, especially for the Office for Standards in Education, meet the targets for tests and exams, live in hope that information technology will come to the rescue and be thankful there aren't 50 pupils to a class each with their own inkwell?
Do-nothing strategies have their merits but by definition fail to advance the status quo. A second option would make the status quo unrecognisable.
It's a very simple solution. All we have to do is arrange for the pound;5,000 of public money, which currently funds each state-educated pupil, to be spent within the classroom and not on the huge, unnecessary bureaucracy outside it. In this way class sizes would be reduced to about six. Six pupils would generate a reasonable salary for their teachers, as well as provide a pleasant working environment with plenty of time for individual support.
One day this will happen, when parents and taxpayers finally wake up to how their hard-earned money is spent.
In the meantime there is a third course of action, one which is on offer right now. Instead of reducing the number of pupils in a class, a similar effect can be achieved by simply increasing the number of adults who are able to support them.
These adults already work in our schools and increasing numbers are being taken on. They are, of course, our teaching assistants.
Many of them are used to giving one-to-one support to pupils with specific needs. They have become essential to the delivery of inclusive education and their commitment and professionalism have been valued by teachers and parents alike.
Many have embraced a much wider role than mixing paints or mounting pictures for classroom displays. Routinely they work with groups and individuals in literacy and numeracy lessons and follow the plans their teachers have given them. Many provide support in other areas of the curriculum such as science, technology, IT and even swimming. The value of having another adult in the classroom to assist directly in the learning process is now widely recognised, but there is more to be done.
Expectations of teaching assistants' skills must be raised still further so there can be no doubt that their deployment in schools brings results from reception through to 16.
They must be appropriately qualified and fully trained so they can work with individuals and groups in all areas of learning and social development. They must be able to supervise whole classes in order to free up teachers themselves to give sustained one-to-one support to their pupils.
Two skilled practitioners with 30 pupils does much more than improve the mathematics of class sizes. It opens the way to provide high quality individual teaching for all pupils so their full learning potential can be achieved. Going down the road of having more teaching assistants in schools is an opportunity not to be missed.
Alan Kerr is a tutor for teaching assistants