History is a facilitating subject, and definitely a cornerstone for your subject choice.
If your school offer Government and Politics, definitely do that.
Geography and Economics would also be great for a Political Science or any humanities / social science degree. Sociology also good for Politics at RG.
English Language / RS, Ethics and Philosophy are fine but not necessarily the "best" you could choose: English Literature, straight Religious Studies or Philosophy, or the above, would set you off better.
History, Government and Politics, Economics and Eng Lit would probably be the best and leave a lot of doors open - but there is much more to be said for your extra reading and interest in the subject, as well as the subjects you enjoy most and would do best in.