The leader of the New Zealand National Party, Don Brash, has resigned in the wake of a party backlash over his attempt to ban a book by investigative journalist Nicky Hager. Last week Brash gained an injunction from the High Court of New Zealand banning anyone in the country from publishing the content of his emails. Hager's book, The Hollow Men: A Study in the Politics of Deception, was set to be released last Tuesday but was blocked by the injunction.