Amber -15.15pm today."Saying you're happy to advantage your own children even if it disadvantages others is at least honest, even if I find that attitude rather depressing. Refusing to acknowledge that the decisions we make affect others is, I think, disingenuous."
Yes.
Which is what I said 20:33 on Tuesday, only more forcefully (and acknowledging that "I wouldn't care"- slight artistic license, for dramatic effect, really!): I quote myself "So, to answer the OP, go, go, go private..... You are buying advantage in a world that tacitly accepts this reality. There is nothing 'wrong' with your choice. Yes, it further entrenches the inequalities that hold back and strangles British Society; it may in future, looking back, be recognised as a massively divisive, unfair and ultimately counter-productive force at work in C21 UK; but, if I had the choice, I'd be buying an education that can ride rough-shod over your DC because, when it comes to one's own DC..... that's all that matters.
And I mean that. Do what you can to advantage your DC over everyone else's..... It's understandable. Just don't tell us you're doing it because of 'the art/drama/sport', thanks."
And not much I've read since changes that!
I 'get' that some state schools are better than others but the thing is, if you look outside the London orbit, you can move into the catchment of many, many good schools and rent to get your DC in. There is some sort of 'way in' if you want to take it. That only applies to private schools if your DC brings something desirable, via a bursary, or more telling, scholarship- to the school. Even if it is only a tick in the Charities Commission box.
I smile at the 'generosity' of Eton bursaries and would wonder what their selection criteria are, also musing the already made point that the DC who would most benefit from very small classes and forensic personal attention- are the least likely to get it.
I would question the Art'n'Sport'Drama'n'Philisophy'n'-what was the rest?- brigade to tell us, honestly, if they'd still pay to model their DC into Renaissance Wo/Man if there were no GCSE results at the end of it? Education for the sake of it, eh? It's very, very easy to claim your only motivation in going private are instilling those disciplines, safe as you are in the knowledge that the individual attention in selective, small, motivated classes that your DC receives, surprise surprise, also results in better GCSE grades! As a wonderful 'by-product'! 
Personally, I still fail to grasp why 7% of our population, merely by dint of a an exclusive (as in 'excludes others') education, get to make the rules, and pocket the money. Whilst I have already acknowledged that yes, there is some sort of correlation between living in poverty and, yes, lower IQ (I said it!), as in 'the clever make money thus can afford choice'- that's not to say I believe that only 7% of the population achieve what they do only via their own, un-advantaged efforts ; and the other 93% get what they deserve. Yes, of course, maybe the 'next' 20% do very well, as well- the MC DC who attend very good state schools, comp and grammar. But the fact remains, the power in this country is united in one thing: Private Education.
There's an awful lot of productive talent lying untapped out there which we, as a society, in our apparent acceptance of the status quo (that privately educated people are 'better') ignore at our peril.
So, back to the OP. By all means go private in order to advantage your DC. It is only 'wrong' inasmuch as if someone is 'advantaged', someone else will be 'disadvantaged'. Which, it seems, shouldn't even enter into it.