David Cameron stumped by Letterman's British history quiz Add to ... AP Video Published Thursday, Sep. 27 2012, 6:44 AM EDT Last updated Thursday, Sep. 27 2012, 10:36 AM EDT British Prime Minister David Cameron's appearance on Late Show with David Letterman is making waves back at home, after Cameron struggled in Letterman's surprise British history quiz. Watch More Video: Christmas cards from B.C.'s gun-toting Santa Claus return Canada stands with people of Ukraine, Harper says Chief Bill Blair says he isn't worried Rob Ford scandal will affect police 'I tend to leave politics to politicians': Toronto Police Chief Bill Blair Kerry talks about Obama Castro handshake Elvis lookalikes take over London's Trafalgar Square Are fracking concerns legitimate? Charlize Theron, Bono and others arrive for Mandela memorial Obama says Mandela 'moved a nation toward justice' Massive crowd at Mandela memorial breaks out into song, dance Desmond Tutu's tribute to Mandela's magnanimity He was one of the world's greatest teachers: Ban Ki-moon on Mandela Obama urges world: Act on Mandela's legacy Bank of England's Carney sees no need to panic Thai PM dissolves parliament in face of protests One-man wrecking crew in Burnaby destroys six police cars 'His courage was undeniable': Joe Biden honours Mandela Former South African president F.W. de Klerk pays tribute to Nelson Mandela British PM David Cameron calls Mandela the 'hero of our time' U.K.'s first upbeat outlook since 2010 Comments AA More Related to this Story Video: U.K. PM Cameron talks politics on Letterman Video: Ann Romney pays visit to Leno Video: Obama: Romney hasn't 'gotten around a lot'