Adrian, I agree with someone in this thread who questioned your ability to "fallback" to Cambridge anytime later. If you're confident that Cambridge is always within your reach, then possibly RHUL is the good choice (how about UCL, it's of quite high reputation?).
Otherwise, I'd say that going to Cambridge is rather research-oriented. Not sure what its MSc entails, but I think its mostly theoretical, which gives you a solid base for boosting your research ability, whatever your interests are. Also, Cambridge has a huge security group as well, with famous people like Anderson, Stajano. And finally, with Cambridge and its recommendations in your record, your PhD applications would look much better. Meanwhile, RHUL ISG is very multi-disciplinary, and has lots of industrial connections, and you know what that means.
Evidently you haven't yet decided your future as a researcher or a professional, which explains your difficulty.
Btw, what are you specially interested in, when talking about security?
Otherwise, I'd say that going to Cambridge is rather research-oriented. Not sure what its MSc entails, but I think its mostly theoretical, which gives you a solid base for boosting your research ability, whatever your interests are. Also, Cambridge has a huge security group as well, with famous people like Anderson, Stajano. And finally, with Cambridge and its recommendations in your record, your PhD applications would look much better. Meanwhile, RHUL ISG is very multi-disciplinary, and has lots of industrial connections, and you know what that means.
Evidently you haven't yet decided your future as a researcher or a professional, which explains your difficulty.
Btw, what are you specially interested in, when talking about security?