SINGAPORE (AFP) - A Singapore court jailed a defiant 76-year-old British author for six weeks on Tuesday for insulting the judiciary by publishing a book critical of executions in the city-state. In the stiffest sentence imposed in Singapore for contempt of court, Alan Shadrake was also fined 20,000 Singapore dollars (15,000 US) for his book based on the long career of a hangman who allegedly put more than 1,000 convicts to death. The previous longest jail term for contempt of court was 15 days. High Court Judge Quentin Loh said he was imposing a deterrent sentence and dismissed a last-minute apology by Shadrake as a tactical ploy to obtain a reduced sentence. Shadrake, a freelance journalist based in Malaysia and Britain, must serve two extra weeks in prison if he fails to pay the fine. I dont have that kind of money, he told reporters. In addition, he will have to pay legal costs of 55,000 dollars, but was given a weeks stay before the jail sentence is carried out while he decides whether to appeal. Shadrake is also being investigated for criminal defamation, which carries a sentence of two years imprisonment, a fine or both. Human rights activists criticised the decision to jail Shadrake but Judge Loh said the allegations of judicial impropriety were without precedent. There is no doubt Mr Shadrakes personal culpability is of the highest order, Loh said during sentencing, noting that Shadrake had openly declared plans to add more chapters to the book. The jail sentence was half the 12 weeks sought by the Attorney Generals Chambers. Shadrakes lawyer M. Ravi said 6,000 copies of the book had been sold. Judge Loh was fair to his client but I wont say (Singapore) justice is fair, Ravi added. Shadrake was arrested by Singapore police in July while visiting the city to launch his book, Once a Jolly Hangman: Singapore Justice in the Dock. It includes a profile of Darshan Singh, the former chief executioner at Singapores Changi Prison who, according to the author, hanged around 1,000 men and women including foreigners from 1959 until he retired in 2006. The book also features interviews with human rights activists, lawyers and former police officers, and alleges that some cases may have been influenced by diplomatic and trade considerations. Singapore executes murderers and drug traffickers by hanging, a controversial method of punishment dating back to British colonial rule. The government does not publish statistics on the death penalty but Amnesty International said in a 2004 report that more than 400 prisoners had been hanged in Singapore since 1991, giving the city-state the distinction of having the worlds highest execution rate relative to its population. In a November 3 ruling that found Shadrake guilty, the judge said the author made his claims against a dissembling and selective background of truths and half-truths, and sometimes outright falsehoods. A casual and unwary reader, who does not subject the book to detailed scrutiny, might well believe his claims... and in so doing would have lost confidence in the administration of justice in Singapore. Shadrakes jail sentence was strongly condemned by New York-based Human Rights Watch. Its a serious blow and it will have a chilling effect on others who have differences or issues with the government, said Phil Robertson, deputy director of the groups Asia division. Amnesty International said sentencing the author to jail was a major step backwards for freedom of expression in Singapore. Shadrake was in a defiant mood at the entrance to the Supreme Court building before the hearing started. He unfurled an Amnesty International Malaysia poster with the words Stop the Death Penalty in front of the media. The poster bore a picture of a womans head covered in a black hood with a noose around her neck.