he ought to have had the answers ready, ummmm - he's the foreign secretary, he's in the cabinet, he should have been there during the policy discussions - or they ought to have put up someone else to do the interview.
I don't have a problem with people unable to remember exact figures and having to look them up; but not knowing about whole areas that the government has been promoting as important just makes him look ... well, charmingly disorganised, I suppose. Can you hear him ruffling his hair at all?