The writing's on the cell wall for US jailbird novelist

It's just as well that Oscar Wilde and John Bunyan, to name but two of literature's greatest jailbirds, weren't sentenced to serve time in the overcrowded state prisons of North Carolina.

Victor Martin, a novelist and career criminal whose four published books were written in his cell in Elizabeth City, is at the centre of a civil liberties dispute, after authorities confiscated the manuscript of his fifth book and attempted to ban him from writing. They allege that the novels break rules banning inmates from conducting business behind bars. Lawyers for Martin, who is nine years into a 23-year sentence for a string of robberies, say the policy violates his right to free speech.

"He's being given a hard time for writing and being told that he's become a threat to the prison," said Martin's publisher, Marcenia Waters. "I'm assuming they're saying that because they believe other inmates might be jealous of him or want to hurt him. But that's plainly wrong. Here is a man, a writer, who is trying to do something positive for himself, trying to build something for when he's released. He wants to come out of prison eventually and be productive in society, and not return to crime. And writing is his get-out."

The move by prison authorities seems particularly pointless, since 32-year-old Martin has not profited from his four novels, which follow the fortunes of a high-rolling Miami career criminal called Unique. Despite the "ban", all his existing books will continue to be sold through Amazon.

Lawyers acting for the American Civil Liberties Union of North Carolina this week wrote to the state Department of Correction, asking for the whereabouts of the confiscated 310-page manuscript. They say that there is "no evidence" that publication of the book, a sequel to his most recently published work, Unique's Ending, poses any danger to Martin or his fellow inmates.

The prison authorities have refused to discuss the case. But Keith Acree, a spokesman for the Department of Correction, told the Charlotte Observer that inmates in North Carolina are prohibited from publishing for payment while behind bars. "The policy prohibits conducting business from prison – not writing," he said.

Although his case now seems likely to become a cause célèbre among free-speech activists, Martin claims to be bemused rather than angry. His work has a following among fans of "urban fiction" – a genre focusing on explicit tales of inner-city crime – and he's convinced the fifth novel will eventually see the light of day. "The way I see it, they want me to stay stagnant here and not do anything," he said.