I'm applying to do particle physics next year, with the hope of eventually getting a PhD, although I have been told that if I do theoretical physics it won't really matter because they're very similar and I can still do a PhD in particle (I know someone starting her PhD in particle with a masters in experimental). Anyway, obviously I want to go to a reputable university (I'm in the UK) as to do a PhD and get a job in pure physics research, apparently where you went is very relevant. I've been looking at the CUG rankings, but where each university is ranked both overall and in physics changes by quite a bit from year to year, making me think that it's almost a worthless thing to consider, because a highly ranked uni right now can easily drop down several places even by next September when I will start. I'm only looking at Russell Group unis, should I just work on the basis that any Russell Group member is fairly reputable and leave it at that or should I try go for the highest ranked ones this year and hope they stay there? I'm at a point where the ones I'm looking at all seem to have equal merits to me and I'm finding it hard to choose one as a favourite.