Some of the replies on this thread make me angry...
There seems to be this misconception that because people are wealthy and/or of a higher social class, and went to a private school,they must be more intelligent. This is just not true. The situation of one's birth has no impact on their intelligence, but rather the opportunity to develop it. I've seen and heard of many people whom are very wealthy, yet are about as stupid as it gets.
I'd even go so far as to say that exams such as A Levels are not a good measure of intelligence, as the current education system relies on students being taught to the test, and being able to answer questions and memorise and regurgitate things.
I'm a reasonable achiever academically, (I'm a B/A grade student), went to a state comprehensive, and hold an offer from a good university (York, one I would probably choose above 'better' universities because the course is perfect for me), yet I would say that I'm much more intelligent than my grades would lead people to believe (and I know that this does seem like something a jealous or whatever person would say), certainly moreso than people at my school who've gotten A/A* grades at A Level.