Shadrake was this week convicted of contempt of court over passages published in his book, Once a Jolly Hangman - Singapore Justice in the Dock, which questions the independence and integrity of the Singapore judiciary.

Gugulethu Moyo, the executive director of Media Legal Defence Initiative, labelled the move a setback for media freedom in Singapore.

"Alan Shadrake's book is a brave and necessary effort to investigate the working of the Singapore justice system in death penalty cases amid intensifying international concern about the administration of capital punishment in the country," he said.

"His conviction today stands as testament to Singapore's determination to cow its critics."

Shadrake's book, published in July 2010, investigates the Singaporean criminal justice system, especially its use of capital punishment. He claims that some well-connected defendants often get off relatively lightly while poor and less well-connected defendants are sentenced to death.

Such criticism follows points raised by organisations, including Amnesty International and the International Bar Association, that express concern regarding the use of capital punishment in Singapore.

Shadrake was arrested after travelling to Singapore on 17 July to launch the book and charged with "scandalising the court". He is also the subject of a separate and continuing police investigation launched for criminal libel.

Shadrake could face a fine and/or imprisonment when he is sentenced on 9 November.