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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Fifteen British WW1 soldiers will be reinterred at the Commonwealth War Graves Commission cemetery today, 100 years after their deaths.
Unresolved complaints about energy suppliers could be five times higher than official figures suggest, according to Labour.