Harry Potter publishers Bloomsbury hit back at plagiarism claims today, branding the allegations "unfounded, unsubstantiated and untrue".
The estate of the late Adrian Jacobs has launched High Court proceedings against the company, claiming copyright infringement.
It is alleged that author JK Rowling's Harry Potter and the Goblet of Fire has similarities to Jacobs' The Adventures of Willy the Wizard No 1 Livid Land.
Today a spokeswoman for Bloomsbury said: "Bloomsbury would like to state that this claim is without merit and will be defended vigorously. The allegations of plagiarism made by the estate of Adrian Jacobs are unfounded, unsubstantiated and untrue.
"This claim was first made in 2004 by solicitors in London acting on behalf of Adrian Jacobs' son who was the representative of his father's estate and who lives in the United States. The claim was unable to identify any text in the Harry Potter books which was said to copy Willy the Wizard.
"Willy the Wizard is a very insubstantial booklet running to 36 pages which had very limited distribution.
"The central character of Willy the Wizard is not a young wizard and the book does not revolve around a wizard school."
Rowling had never heard of Jacobs, or "seen, read or heard of his book" until the claim was first made - seven years after the first Harry Potter book was published, the spokeswoman said.
The estate also claims that Jacobs approached Christopher Little to be his literary agent, and Mr Little later went on to represent Rowling.
Mr Jacobs died in a London hospice in 1997.