ITV News' Libby Wiener reports from Sao Paulo in Brazil where Prime Minister David Cameron is on a two-day visit.
The Conservative, who appeared on America's Late Show with David Letterman on Wednesday night, was quizzed by the veteran host over his knowledge of British history.
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Stanley May - who was a regular at the supermarket in Truro in Cornwall - hit his head on the wet floor.
May has implicitly admitted that her flagship manifesto pledge was not properly thought through.
American superbike racer Nicky Hayden has died - days after being involved in a serious bicycle collision with a car.