Don't worry, in my MSc class I was the only white Brit out of the entire group.
Maybe becasue a lot of very good foreign students apply?
There probably should be basic language requirements thoguh.
Someone mentioned it previously as well, the government still subsidises higher education (albeit lesser now) and thr price that international students pay is actually the full annual cost of the university (therefore they get the same amount of money per student).
London is also a pretty multicultural area and since foreign students flock there as they've heard good things about it (and perhaps can afford to actually live there) there'll probably be a higher number of foreign students. In other cities/towns this may not be the case as accommodation and living costs are lower
Even if no one inside the British universities was British, so what ?
You get inside university based on merit, not your nationality, or your race, or your religion or whatever.
Look at Japan and Korea. Everyone looks and sounds the same and they are very homogeneous and their society is boring because of it, and they also have the highest suicide rate in the world, so, there you go.
Firstly because the government allows hordes of foreign students to come here as a work around for economic migration because many of them then get internships (also encouraged by diversity policies) and then they stay. Utter and complete betrayal by our own leaders.