I studied Physics in King’s College London. I also know UCL and Royal Holloway somewhat.
Royal Holloway (and Bedford New College) campus is way outside london near Staines and Egham, it is quite a nice area, but not anything like being in the city. It used to be an all girls college, and at the time I looked into studying there it still had a very high percentage of female students.
University College London (UCL), is near the administrative center on The London University, and right next to the SOAS (School of Oriental and African Study) which is an interesting place. UCL is very well placed in the centre of London.
Historically UCL and KCL are at a par, whilst Royal Holloway maybe a little less achidemic.
King’s College London (KCL), is On the Thames near Waterloo Bridge, near The London School of Economics (which is an interesting place, especially if you have an interest in pollitics). KCL is also very sell placed in the center of London.
KCL and UCL are historical rivals, originally UCL was created as a modern forward thinking colledge in central London (this was in the early 19 th century) and allowed such people as Women and Jews to study). Due to the scandal of allowing Women of all people to study, King’s College was set up soon after by Royal Charter to reafirm ‘good’ Church of England morals with a propperly restricted access university in the center of London. Though nowadays both Univerities are very open to any students and both a quite Liberal (very Liberal by USA standards) the old rivalry still exists in competitive sport and similar.
Recently I know that KCL internal politics and descision making is dominated by the Liberal Arts faculties, so I would not suggest people should go there to study Science, conversely this probably makes it a good place to study English or Ancient History.
I susspect that UCL may have an edge over KCL for Ancient History simply due to its closer proximity to the London Museum which holds an incredable number of Ancien Artifacts.
Similarly I would susspect KCL may have an edge over UCL for Lae study simply due to its closer proximity to the Law Courts which are the main courts in the country.
Both KCL and UCL have separate Medical universities. And campuses away from the main campus location.
Please feel free to email me (see my profile) if you have further questions.