More recently, the Sutton Trust, an educational charity, found that of the country's 100 leading journalists - national newspaper and broadcast editors, columnists and news presenters - more than half had been to fee-charging schools and 45% to Oxford or Cambridge.
The claim is about one specific profession, one which is very much over-subscribed so networking is very important, and looking at one particular statistic. If you look at the 100 "leading" people in any field, many of them will be older and will not necessarily give a fair representation of those coming up in the ranks. Journalism may well still be unfairly dominated by certain groups, but one needs to look at more than the 100 "leading" journalists to determine this.
Amongst my colleagues (different field), those in their 50s who were educate in the UK are primarily grammar school or private school educated. This then automatically implies that almost all UK vice chancellors (who are in their 50s or older) are grammar or privately educated. But, if we look at people now being hired in their 20s and 30s, many are international and those educated in the UK come from a very diverse range of backgrounds and schools.
I also take issue with using "45% went to Oxford and Cambridge" as code for "unfair dominance". Oxford and Cambridge are highly over-subscribed universities. They select from a large pool the students who have the most ability and potential at 18. They then give these students a world leading education, with one on one time with world leading academics (which most other universities cannot afford to offer). It is not surprising nor is it unfair in itself that many Oxbridge graduates go on to be very high achievers in whatever field they enter.
It is unfair if an Oxbridge graduate is hired just because they come from Oxbridge. It is not unfair if the Oxbridge graduates are hired because they have very high ability and very strong skills. In some professions the first may well occur (I don't know) but in the areas I know Oxbridge graduates are hired for their abilities and, in particular, problem solving skills rather than because of networking. At the same time, the Oxbridge dominance is fading as other UK universities catch Oxbridge up: again looking specifically at my area it's not just Oxbridge graduates who do well, one could point to several other top UK courses which consistently produce highly desirable graduates.