Talking to people who are consultants they said that (and this is the example he gave so don't hate me) was if you are deciding between someone who went to Cambridge and someone who went to Plymouth you would be more inclined to look at the Cambridge graduate and therefore hire them. Other than Oxbridge, Imperial and UCL it doesn't really matter where you go as everyone receives practically the same training- its just the reputation that certain unis have for being extremely hard to get into that makes the differemce