Ricky Gervais facing legal action from rival author over children's book
John Savage, 44, has lodged a writ claiming the book, being made into a multi-million-pound Hollywood film, was based on his 1998 book Captain Pottie's Wildlife Encyclopaedia.
The writ states Flanimals is "broadly the same in content and character" as his book.
He said both books "involve a whimsical take on the animal kingdom through the use of drawings and text, which in the case of the latter is a copy, in form and substance, of the former". Mr Savage, from Norwich, says he has "suffered significant financial hardship and loss" and "damage to his reputation" as a result.
He said he submitted his book to a number of literary agents including Peters Fraser Dunlop (PFD), who rejected it, before it was finally published in 2000.
PFD later represented Gervais, who made his name in the BBC comedy The Office, when Flanimals was published in 2004.
The book has led to several spin-offs and a CD. Mr Savage is claiming "an unspecified sum" from the profits and the destruction of the remaining copies of Flanimals.
If the parties are unable to resolve the dispute it could go before a High Court judge.
A spokeswoman for Ricky Gervais said: "This story goes back several years, when John Savage first made contact with Ricky Gervais' representatives. At the time, it was made clear that the concept and illustrations of Flanimals pre-existed John Savage's work."