Judge David Kitchin who is overseeing the plagiarism case at London's High Court said in a ruling on Thursday that the claims made by Paul Allen, trustee of the estate of the late writer Adrian Jacobs, were "improbable."
But he also turned down an application by lawyers for Rowling and her British publisher Bloomsbury for an immediate judgment dismissing the case outright. "Even at this early stage, the judge has concluded that the claim may succeed at a full trial," said Allen's lawyer Nick Kounoupias. "If the claim does proceed then J.K. Rowling and Bloomsbury will be required to explain how the similarities between the two works came about," he added. The judge is expected to order Allen to pay a sum of money to the court as a security against the costs of the case should it eventually go to trial. That "conditional order" will be made at a later hearing, possibly before the end of the year.
Legal experts say the costs would be "substantial".
Bloomsbury denies allegations that Rowling copied "substantial parts" of "The Adventures of Willy the Wizard No 1 Livid Land," written by Jacobs in 1987.
Jacobs' estate has said that the plot of "Harry Potter and the Goblet of Fire" copied elements of the plot of "Willy the Wizard," including a wizard contest, and that the Potter series borrowed the idea of wizards travelling on trains.
Rowling's book, published in 2000, was the fourth instalment of the hugely successful Potter series the stories about the British boy wizard that have sold more than 400 million copies worldwide and been turned into a multi-billion dollar film franchise.