In September I'm going to be starting a course in physics/philosophy at king's college London. My ideal plan for the future is to postgrad (ideally doing something theoretical) at the most reputable place I can get into, a goal that was hindered a bit by my oxbridge rejection. To those who might know anything about it, does the KCL physics department have much, if any, prestige comparatively? If I get a good enough degree in London, would I be able to postgrad at a "world class" institution, i.e. oxbridge or the Ivys? I apologize if I'm thinking too far ahead, or if this isn't the sort of question to post here.