A levels for International Relations / Politics

I've just started my a levels and phase 2 course changes have just opened. I'm currently taking English Literature, History and French and I'm unsure whether or not I should change either English or history to economics. I'd like to know which one is more helpful for an international relations/politics degree.
PS. I would like to be a diplomat when I'm older so that's the career path I'm aiming to follow.