Michael Rosen: Getting over it, and getting through it

"Passionate linguist, gifted humanist, national treasure and ambassador of gibberish" is a judge's description of this year's PEN Pinter prize winner, Michael Rosen. The British poet, author and performer has written more than 200 books, including Sad Book, which chronicles Rosen's grief over the loss of his son Eddie, and children's classic We're Going on a Bear Hunt.