"There's one myth to start with. The suggestion that in fully selective areas there are grammar schools and comprehensives.
But those fully selective areas you refer to are few in number. Trafford, Buckinghamshire, Slough, Torbay, Southend, Kent and Medway. So in the majority of authorities it is not true to say that non-selective schools are secondary moderns.
Increasing demand has led to steady expansion of existing Grammar Schools in these areas. Many of the 164 Grammar Schools have 10 applications for every place.
A further 29 authorities offer a mix of GS/Comp/SM (sometimes now called High Schools, Community Colleges or All-Ability).
Which leaves 138 fully Comp LEAs.
The real myth is that there is no selection in non-selective authorities. In fully Comp areas selection is based on what catchment area you can afford to live in - social selection - rather than the 11 plus. There are excellent, good and bad Comps just as there are excellent Grammars, good Comps/SMods and bad Comps/SMods.
There are parents with academically talented kids who will move to a selective area for the perceived educational opportunities. There are parents who will move to the catchment area of a good Comp or a specialist Arts/Science/Language/Performing Arts/Languages school for the same reason.
The real myth is that there is no selection in "non-selective" areas.
Of the 100 most socially selective schools in the country, 91 were comprehensives, eight were grammars and there was one secondary modern.