It is a mixture.
But it is no ones fault per say. Therr are defining stats about over-achieving chinese peopoe, under-achieving pakistani people, and white people who cannot even spell their name. It is not Oxfords fault, the society we live in plays a small (but influential) role in the construct of academic success of various different races, but a lot (imo) has got to do with the way they have been brought up.
If your parents are educated/well off/cultured/academically pushy it will be naturally easier for you to do better at school.
Unfortunately not all people come from a background like that.
I'm white, my sister got pregnant in her last year of school and I have a brother who passed away in hospital after getting into gang fights. I came under a special scheme organised by the uni which frankly was there to help chavs and people from ****ty backgrounds achieve and get into Uni. It was not the Unia fault that no one in my family had got any form of higher education or that most of my family were on benefits etc. yet they made allowances to 'widen participation'
Cameron is a cock for even bring race into it. Yes more should be done to get under-achievers reaching their goals etc but it has nor much to do with colour explicitly. There are tonnes of brainy/well off black people but even more less fortunate black people without a stable household. There ought to be some way of bridging the gap and helping all student who aspire to go to uni but who are held back by the social dyna,ic of their household - be they white, black, yellow, orange w/e.
Don't blame Oxford, don't blame the government. Social equality is an issue for all of us and there is no way of fixing it unless we take serious steps in educating and providing for those who cannot themeselves. Our government gives financial aid to families without income so why do we not give academic help to those who cannot access it/have low academic prospects purely due to a factor OUT OF THEIR CONTROL?!?!?! It's not fair. It's not right.