Harry Benson on his life of photos

Harry Benson says he first "hit the big time" when he caught the Beatles having a pillow fight on camera. This gave him the opportunity to travel with the Fab Four to America for their 1964 tour, which took the band truly global. Since then Benson has been called upon to photograph every U.S. President from Dwight D. Eisenhower to Barack Obama. He's marched alongside Martin Luther King and taken intimate pictures of just about every cultural icon from Frank Sinatra, to Michael Jackson and Amy Winehouse.

Now he's celebrating 50 years behind the lens with an exhibition of his half-century of work at the Mallett Gallery in London. We asked him to talk us through his favourite pictures and the memories behind them.