What questions should Letterman have asked David Cameron?

Appearing on David Letterman's chatshow in the US on Wednesday night , David Cameron had to undergo a mock citizenship test. The prime minister struggled to give the literal meaning of the words 'Magna Carta' and couldn't name the composer of Rule Britannia, though you might argue that such linguistic and musical trivia is only of marginal relevance to Cameron's job. If you had been in Letterman's seat, what questions would you have asked? What aspects of British history or society do you think it's important for a prime minister to know? Come up with a set of questions, and we'll turn them into an alternative mock test that we'll publish on the site later today.