Once again on this site, everyone's wrong about what uni you need to get into IB - on one hand people like Drogue seem to think if you're not from a top 5 uni you have no way in hell, whereas other idiots seem to think uni doesn't matter, the individual counts (what a load of sh*t!).
I have seen the CV books of new graduates at several leading investment banks - it's normal for each bank to distribute a "facebook" like this, and for peers at other places to swap them for excellent networking opportunities.
For decent (ie GS, Citi, MS, ML, UBS, DB, BarCap, Lehman) banks in the FRONT OFFICE (the highest earners, the people who actually make the primary profit), easily the majority of British grads studied at either LSE or Oxbridge. Then each bank/division combo will have a small handful from places like Warwick, Imperial, UCL, Nottingham, Bristol. You will occasionally get 1 star candidate from somewhere like Edinburgh, Manchester, Birmingham, but this is quite rare.
For the MIDDLE OFFICE, unis around the top 7-15 are a lot more prominent - namely Sheffield, Edinburgh, Loughborough, Leeds, Durham, St Andrews etc.
For the BACK OFFICE, any idiot can get in pretty much. Operations is monkey work that a 14 year old kid can do, so they accept candidates from almost any uni, including the better ex-polytechnics.