A sequel to worldwide bestseller To Kill A Mockingbird will be published later this year.

The book, by author Harper Lee, is called Go Set A Watchman and is set in the 1950s and will feature many of the book's original characters.

To Kill A Mockingbird, set around a trial in the racially-divided deep south of the United States, has sold more than 40 million copies.

To Kill A Mockingbird and its central characters, sister and brother Scout and Jem and their lawyer father Atticus, were brought to life in a 1962 film starring Gregory Peck.

Lee, 88, said: "In the mid-1950s, I completed a novel called Go Set a Watchman. It features the character known as Scout as an adult woman and I thought it a pretty decent effort. My editor, who was taken by the flashbacks to Scout's childhood, persuaded me to write a novel from the point of view of the young Scout.

"I was a first-time writer, so I did as I was told. I hadn't realised it had survived, so was surprised and delighted when my dear friend and lawyer Tonja Carter discovered it. After much thought and hesitation I shared it with a handful of people I trust and was pleased to hear that they considered it worthy of publication. I am humbled and amazed that this will now be published after all these years.'

The new book, which tells the story of Scout's return to her native Alabama from New York to visit her father, will be published on July 14 by William Heinemann who were the original UK publisher of To Kill a Mockingbird.

Tom Weldon, CEO of Penguin Random House, said: "To Kill a Mockingbird is one of the most important and enduring books on the Penguin Random House lists and it is no surprise that time and again it is voted best loved by both the reading public and by educators.

"The story of this first book - both parent to To Kill a Mockingbird and rather wonderfully acting as its sequel - is fascinating.

"The publication of Go Set a Watchman will be a major event and millions of fans around the world will have the chance to reacquaint themselves with Scout, her father Atticus and the prejudices and claustrophobia of that small town in Alabama Harper Lee conjures so brilliantly."