J.K. Rowling talks about launching her first novel for adults

After months of hype and anticipation, J.K. Rowling's first novel for adults, The Casual Vacancy has appeared, swept into the arms of hopeful booksellers – and an army of grown-up Harry Potter fans eager to find out what his creator has done next.

Rowling told a 1,000-strong audience at London's Southbank Centre on Thursday evening that the idea for the book, a "local election sabotaged by teenagers," came to her on a plane several years ago.

A gritty and darkly humorous tale of ugly realities in a pretty English village, The Casual Vacancy has been given a mixed reception by critics.

Writing for a more adult readership, Rowling said, had been "freeing," though "in other senses it's a challenging book," told from multiple viewpoints.

The book's sex and swearing have drawn the most comment so far, some audience members were startled to hear the F-word pass Rowling's lips during Thursday's reading.

But the presence of death is perhaps the book's most adult element, and one that loomed over Harry Potter's world, too.

Rowling did warn fans during the question and answer session, "it is a humorous book, some of the humour maybe quite dark in places”.

Five years after the last Potter book appeared, Rowling remains the world's most successful living writer. The Casual Vacancy is already at number one on Amazon's US Chart.