Image caption JK Rowling recently announced she was working on a Harry Potter stage play

The lawyer who revealed crime writer Robert Galbraith was actually Harry Potter author JK Rowling has been fined £1,000 for breaching privacy rules.

Chris Gossage, a partner at Russells Solicitors, has also been issued with a written rebuke from the Solicitors Regulation Authority (SRA).

He confided in his wife's best friend that Rowling had written The Cuckoo's Calling under a pseudonym.

It was then publicly revealed by The Sunday Times in July last year.

Rowling took legal action later that month against Gossage and his friend Judith Callegari, who had revealed the information during a Twitter exchange with journalist India Knight.

Rowling accepted an apology from the law firm and substantial damages, in the form of a charity donation.

In a ruling issued on 26 November but made public on 30 December, 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.

The breaches 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".

Image caption Extra copies of The Cuckoo's Calling were printed to cope with demand once Galbraith's true identity was revealed

'Private conversation'

Rowling, who had only told a "tiny number" of people about her pen name, said she had assumed she "could expect total confidentiality" from Russells Solicitors.

"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."

The law firm said Galbraith's true identity was revealed by Gossage "during a private conversation" and that "the disclosure was made in confidence to someone he trusted implicitly".

The Cuckoo's Calling, about a war veteran turned private investigator, had originally sold just 1,500 copies but within hours of Rowling being publicly named, it had risen more than 5,000 places to top Amazon's sales list.

Rowling decided all royalties should be donated to The Soldiers' Charity.

On her website she said she had found it a "liberating experience" to be able to publish "without hype or expectation", compared to the attention that had greeted each of her bestselling Harry Potter novels.

She added: "To those who have asked for a sequel, Robert fully intends to keep writing the series, although he will probably continue to turn down personal appearances."