"kathy - there may be some people who genuinely believe that there should be no selection by ability"
well it seems to be a fairly widespread view among the political classes Violet - Charles Clarke in particular made some fairly extreme statements along those lines when he was education sec!
You only have to look at the negativity the G&T programme attracts (and again, there is a LOT wrong with it, but a lot of people's objections to it are simply per se) and the way opportunities to select in other ways (eg by aptitude in specialist schools) have met with opposition, to see that there is a great deal of general hostility to the principle of academic selection of any kind, not just to the idea that we should go back to grammar schools as they used to be.
Personally, if bright children had an entitlement (a real one, not just theoretical) to a particular kind of academic education (say, triple sciences, a good variety of languages not just French and Spanish, the opportunity to work with other children of similar ability sometimes, the opportunity to work at a pace suitable to their ability, maybe even IB or IGCSE if necessary) it wouldn't bother me whether it was delivered via a comprehensive or grammar school system and indeed I can of course see the social advantages of comprehensives. Of course it would be better if the local school catered for all abilities, rather than for them to need to turn a city comprehensive into a grammar so bright children from outside the city would have to travel several hours a day and not go to school with their mates from primary. But I suspect that ultimately it would be much harder to achieve than simply allowing the academic children who are not being catered for by the comprehensive to be selected by ability by a school that already offers that kind of thing to start with