Whenever I hear wailing and gnashing of teeth over the lack of social mobility in today's Britain, I think of the 1980s theorists who told aspiring teachers not to correct pupils' - or rather learners' - regional dialect, impose on them our own cultural and moral values or mention the works of over-influential Dead White European Males such as Mozart, Da Vinci or Dickens (Shakespeare is still acceptable, I understand - but only in modern dress or rendered in Jamaican patois).
It was not always thus. Once upon a time, there were teachers who devoted heart and soul to introducing their pupils, however poor or deprived, to classical culture, correct grammar in speech and the kind of general knowledge and manners that would equip them for any social situation - anathema to the progressive educationalists, whose socialist hackles rose at the idea of the noble working class aping the aristocracy.
Before the progressives took control and weeded out those who wouldn't toe the line, and in the days when career opportunities for women were considerably more limited,the profession attracted many intelligent and rational people with a strong independent streak. One of them was a great-aunt of mine whose personality made her a force to be reckoned with; she would never have been prepared to conform sufficiently to fit in with the modern profession but, in her day, she did a great deal of good in a deprived industrial town.
Being a born educator with no children of her own, she saw it as her role to instruct the younger members of the family at every possible opportunity; I've been reminded of one particular childhood lesson by both the question of foodbanks and by Julia's post today.
It was the mid 1970s and we were out shopping in her home town, where a substantial number of the inhabitants were overweight and clearly unfit. When one particularly large young woman lumbered by sipping a fizzy drink, my great-aunt sighed and said that that it was a shame that malnutrition was such a problem in a supposedly civilized country.
I was baffled; I had seen pictures of starving Ethiopians on Newsround - wasn't that what malnutrition looked like? My great-aunt patiently defined the term and explained that we were seeing the effects of a poor diet, with a lack of vitamins and protein and the over-consumption of sugar and starch, a diet at odds with the cheap and plentiful produce in the market where we were.
The worst thing about it, she said, was that those young women, through either ignorance or idleness, would be unlikely to ensure that their children or grandchildren had a proper diet and learned not to over-indulge in treats; the consequences for future generations would be painful for them and expensive for the rest of us. Government intervention would accomplish nothing; they - and their children - should be taught to think and act for themselves.
Four decades on, it looks as if she was absolutely right. She died before I was old enough to appreciate it, but I owe her a great deal; she taught me never to trust politicians or journalists and to regard with deep suspicion any religion that requires of its followers a combination of blind obedience and large families.
While teachers like her can still be found, many of them are now in the private sector, away from the demands of state bureaucracy, ideological imperatives and unreasonable management policies - though it was once common practice, what teacher, now, would dare offer individual help outside school to a promising pupil from a deprived background? The teacher training establishments have ensured that a high proportion of those who reach the classroom under their aegis are herd animals rather than independent thinkers.
If social mobility is to be increased, the answer is not to abolish private education but to give state school pupils the opportunity to experience what the progressives took away.