Harper Lee's go set a watchman 'most popular book on Amazon since Harry Potter

Harper Lee's Go Set a Watchman has become the most pre-ordered title on Amazon since the final Harry Potter book, the online retailer has said.

The opening chapter of the highly-anticipated novel by the reclusive author of To Kill A Mockingbird was published for the first time on Friday.

The chapter ran in The Wall Street Journal and The Guardian.

The novel, which is currently the number one best-seller on Amazon.com, is due to be published on 14 July.

Amazon did not give any figures for pre-orders, but publisher HarperCollins said it had ordered an initial US print run of two million.

Lee wrote Go Set a Watchman in the mid-1950s - but her editor persuaded her to turn some of the story's flashback sequences into a separate novel.

That novel became To Kill A Mockingbird, which went on to win the Pulitzer Prize in 1961 and has sold more than 40 million copies worldwide.