Kalwejt, I'm unsure what would ever qualify me for the position of Secretary/Minister of Defense--even upon completion of any graduate or postgraduate work I might do--but I'm honored nonetheless. My utter lack of a foreign policy "vision" (or rather my possession of too many of them) would lead to a strange and garbled tenure that would no doubt lead Wikipedia readers scratching their heads for years after.
I think you underestimate yourself, but assuming you're right, the beauty of the British system is that one doesn't have to be an expert in the ministerial area entrusted to him. I mean, what kind of diplomatic/foreign affairs experience John Major had, when he was suddenly picked as Foreign Secretary?