Warning, anecdotal

I got BBB in my A levels (easy, non-science A levels) in an awful state school, applied for and was accepted on an 'American Studies' degree at Nottingham uni. 6 months later I dropped out.

I applied to study maths, further maths, chemistry and physics at a 6th form college and got 90%+ in all of them. I'm now studying chemistry at Imperial.

Grades should be weighed against the average grade of the school. A B grade in my old crappy school should be worth an A grade from Eton.

EDIT: BTW Americans, our tuition fees are a LOT less than yours are. We pay £3K a year (up from £1K 3 years ago) and the govt pays the remaining £18K (figures correct for my course at least). We also recieve a grant (up to £2K) depending on the students financial circumstances and big, low interest student loans that presumably the govt subsidises.