There is a lot more to say about this mixing-with-all-strata-of-society-at-school issue.
This country is about as non-socially-mobile as it has ever been. The situation was probably better in the late middle ages, when a bright boy could become a priest (which is how Cardinal Thomas Wolsey, son of a butcher, became the most powerful man in England,apart from the king).
Things were much more mobile even 30 years ago - talent could rise academically and economically. What made that possible within the education system? Grammar schools (almost all gone in the last 30 years), the assisted places scheme, whereby bright children could go to the best private schools on government assisted scholarships (now abolished), a well-paid, intellectually-independent and socially honoured teaching profession mostly staffed by graduates of good universities who helped their brightest pupils aspire high, whether they were from leafy Berkshire or a sink estate in Newcastle.
That has been progressively undermined by the working conditions of the last 20 years (centralised government deciding syllabus and teaching styles, centralised testing every five minutes, mountains of paperwork, abusive treatment at the hands of pupils and parents... I know lots of bright and inspiring and subject-passionate people who go into teaching. Some of them have even done a year beyond the NQT year before they've had enough and go to private schools or leave the profession altogether. Those who are left are those with a real vocation, but their job is damn tough. They have my undivided admiration, but I still think the majority of parents can do better for their children than the teachers can manage given their working conditions).
The abolition of the university grant and introduction of student fees didn't help either.
The truth is that we live in a class-ridden society and perhaps the best way to opt out of its prejudicial structures is to opt out of some of its institutions - like schools, for example.