LONDON - The lawyer who blew the cover of Harry Potter author JK Rowling when she wrote a crime novel under a pen name has been fined £1,000 (1,200 euros, US$1,650) for breaching the privacy rules of his profession.
Chris Gossage confided in his wife's best friend that Rowling had written "The Cuckoo's Calling" under the pseudonym Robert Galbraith.
Gossage has also been issued with a written rebuke from the Solicitors Regulation Authority (SRA).
Rowling took legal action against Gossage and his friend Judith Callegari, who had revealed the information in a Twitter exchange with Sunday Times journalist India Knight.
Rowling said at the time she was "angry" after her pen name was then publicly revealed by the Sunday Times in July last year.
Rowling accepted an apology from Gossage's law firm Russells Solicitors and substantial damages, in the form of a donation to a charity for army veterans.
In a ruling made on November 26 but only made public on December 30, the SRA said that "by disclosing confidential information about a client to a third party" Gossage had breached several principles of its rules and code of conduct.
They included failing to "act in the best interests of each client" and a rule that members should "behave in a way that maintains the trust the public places in you and in the provision of legal services".
Rowling, who had only told a "tiny number" of people about her pen name, said she had assumed she "could expect total confidentiality" from the law firm.
"I feel very angry that my trust turned out to be misplaced," she said in a statement in July.
"To say that I am disappointed is an understatement."
Russells Solicitors said Gossage had revealed Galbraith's true identity "during a private conversation... to someone he trusted implicitly".
"The Cuckoo's Calling", about a soldier who lost a leg fighting in the Afghanistan war and became a private investigator, rose more than 5,000 places to top Amazon's sales list in Britain after the true identity of its author was revealed.