A Russian reworking of JRR Tolkien's The Lord of the Rings has been made available as a free download after being translated into English as a labour of love by a fellow Tolkien fan. But Society of Authors general secretary Mark Le Fanu warned that even non-commercially distributed titles must be licensed by the copyright owner, in this case the Tolkien estate.

The Last Ring-Bearer, by palaeontologist Kirill Yeskov, retells Tolkien's epic story from the perspective of the region of Mordor, from where Sauron, the Dark Lord, waged war on the free peoples of Middle Earth in the War of the Rings, eventually to be defeated by Gandalf. The 140,000-word novel, published in Russia in 1999, takes as its hook the idea that Tolkien's own text is the romantic legend of the winning party in the War of the Rings, and that a closer examination of it as a historical document reveals an alternate version of the story.

The Last Ring-Bearer is well-known among Russian fantasy fans, but according to translator Yisroel Markov, publishing houses have not been prepared to publish an English translation because of legal concerns. He himself had been "impressed enough by this work to spend a few dozen lunch hours translating it to English", and the novel has now been downloaded from file hosting sites thousands of times, he said.

David Brawn, estates publisher at HarperCollins, Tolkien's exclusive publisher, said: "To my knowledge, none of us have ever been approached to publish this book." Russia has operated outside copyright "for years", Brawn added, though the situation is now changing. "Online there are lots of infringements which it is extremely difficult to do anything about," he said. "When you get something as popular as Tolkien, fans want to create new stories. Most are pretty amateurish. Tolkien himself isn't around so it's the estate's view that it's best to say no to everything. If you let one in, you'd open the floodgates."

Mark Le Fanu, general secretary of the Society of Authors, warned that fan fiction made available non-commercially was not exempt from copyright. "If the book's available in English without a licence from the copyright owner, that's copyright infringement," he said.