I came from a very ordinary background - no money, a tied cottage with neither bathroom nor flush toilet - but both my parents had matriculated, which seems to have been a sort of O Level equivalent in the 20s. I went to a small village primary school - fewer than 100 pupils - in Mid-Surrey. But the headteacher believed passionately that the 11+ was a life-changer, and so I and one or two others were pushed quite hard. I took my 11+ a year early, and was somewhat taken aback to arrive at Grammar School and discover I was quite ordinary.
I left with a modest haul of O Levels and a couple of A levels, joining a nationalised industry. The local secondary modern was divided in two the year I started Grammar School, with the girls having a new school next door to ours. When I entered the 6th Form, a girl from the SM school joined us - she had 9 O Levels, got 3 A Levels, went on to study Architecture at Newcastle Uni. Failing the 11+ was not the end of the line even then.
The day I started primary school my twin brothers were born, which was a bit tough. When they started school, the old headmistress had retired, so the pushing days were over, but they both went to the same Grammar School as I (and DW Ashcombe) had. One became Head Boy, went to Cambridge where he got his PhD, retired a few years back as Head of Department at the Uni of Marseille. The other, sadly no longer with us, was Captain of First Eleven, graduated from Durham Uni, became a social worker, reflecting his political beliefs.
I believe that civilisation got where it has by giving people their head. Thus state Grammar Schools cater for those who, at 11, are able to step up to them. But, as I showed above, late-flowering talent can still out from a secondary modern school. They are not a dustbin, and with decent teaching pupils can still excel and fulfil their potential.