<p>Sorry, I see now. Well, that’s not something I considered but it does make sense, since PhD students have a role in teaching undergrads that they don’t in the UK. I think that’s a benefit for PhD students, since it’s valuable experience to have. It’s of dubious benefit to the undergrads who are taught by PhD students instead of the profs themselves, but that’s another argument for another day. :)</p>
<p>Fair enough, you know plenty of British students doing their PhDs in the US, but there are 60 million people in the UK and you only know a very select group. They clearly felt they had reasons for moving, or else they wouldn’t be there. That doesn’t mean everyone back in the UK agrees with them. </p>
<p>I’m not sure why you’re bringing that mathematician into this, as it doesn’t seem to have any bearing. Academics move between universities all the time, and the UK has been known to steal the odd academic from top American unis as well. Regarding the strength of maths in the UK, Cambridge has had 7 Fields medallists and 5 Nobel Prize winners in the field of Maths, and remains one of the strongest maths departments in the world.</p>