From John Clare's most recent Telegraph readers' questions answered column:

Why can't schools be left to choose their own pupils? What need is there for busy-body local education authorities, admissions forums and appeals panels to intervene?

According to Philip Hunter, who glories in the title of "chief schools adjudicator", the answer is as follows: "Where a school can choose children, it will, left to its own devices, inexorably drift towards choosing posh children. Teachers would rather deal with nice children who have done their homework, and parents would prefer to send their children to schools that cater for children with similar backgrounds. The result is high-performing schools in posh areas and less well-performing schools in deprived areas." If nothing else, you have to admire the brutal clarity of the argument. The notion that schools can be improved so that all are equally attractive is "pie in the sky for the present", Mr Hunter adds.

I reckon he's right about the "pie in the sky" bit, and not just "for the present" either.

His solution? Parents must learn to accept that the bureaucrat who dispatches their child to a poor-performing, unpopular school knows best.

Mr Hunter is the Fixed Quantity of Education Fallacy personified. Yes, posh schools would get posher, if all were allowed to choose. But can he not see that the unposh schools would face pressures on them to get posher too? Especially if people were allowed to take a crack at setting up posh schools for the unposh, so to speak. Mr Hunter seems to think that posh kids have a fixed quantity of educational virtue attached to them, which shines out on its surroundings, uplifting all in their vicinity, and the only question is: who gets to bask in the light? And the unposh kids will automatically be illuminated, no matter what the other influences of their immediate surroundings. But what if the unposh kids extinguish the lights in their midst rather than passively allowing themselves to be illuminated?

What, in other words, if his rearrangements reduce the total amount of illumination? What if the arrangements he forbids would greatly increase it?