Stream the schools not the children
This is a political comment, and my political comments tend to get downvoted. But here goes, anyway.
The education system is failing at all levels. It fails to properly develop the bright children because it stuffs them (*) into bog-standard comps. About 20% of children used to get a grammar school education. That means about 20 out of the 100 or so children admitted to a comprehensive each year at age 11. So in a class of 30 there are already 10 not really at home there.
Fast forward to age 14, when they begin to specialise into STEM, foreign languages, history, etc. and there are maybe 12 bright STEM children. What state school will provide their own classroom for those 12? Let alone the class of teaching that the top 5 deserve?
The system also fails those at the other end of the scale. There are not enough of the weak ones to justify giving them special attention, just as with the bright ones.
Finally, the system fails the average child; the two-thirds or so at average IQ (100) plus-or-minus one standard deviation (15). Their classes are distracted or disrupted by the minority groups who should be elsewhere, preferably in separate schools dedicated to their needs.
We need bright schools, midstream schools, and weak schools. With this separation, the midstream schools could do a much better job, and would meet the needs of many employers.
I suspect there are no policy-making civil servants in the Education Department who understand the terms mean and standard deviation, let alone the quantitative implications I have set out above. Instead they witter on about the number of pupils receiving free school meals.
I emphasise the requirement for STEM graduates in policy-making positions. The old civil service doctrine, "On tap, not on top", has been the ruin of modern Britain. Fix that, and a lot of other things will get fixed.
(*) So to speak.