Cambodia’s war crimes tribunal today handed down its first guilty verdict against a senior Khmer Rouge figure, Tuol Sleng prison director Duch, for crimes committed under the regime more than 30 years ago.

Judges at the United Nations-backed court sentenced Duch to 35 years in prison. However, they reduced his sentence by five years after ruling that he had been illegally detained by a military court following his arrest in 1999.

Duch's prison term was reduced by a further 11 years for time served, meaning that he faces a total of 19 years behind bars.

Duch, whose real name is Kaing Guek Eav, was convicted of crimes against humanity and war crimes for his role at Tuol Sleng, or S-21, the regime’s most important interrogation centre where as many as 16,000 men, women and children were brutalised before being systematically exterminated.

Only 14 people are known to have survived Tuol Sleng, which under Duch’s meticulous and rigid hand evolved into an efficient killing machine that came to symbolise the worst excesses of increasingly paranoid Khmer Rouge leaders.

Entire families were imprisoned for the alleged crimes of a single member, and on a single day in 1977 alone, Duch ordered the executions of 160 children.

The verdict marks the first time that a Khmer Rouge official has been convicted by an internationally recognised court for crimes committed during the 1975-79 communist regime, which dismantled modern Cambodian society as it sought to build a classless agrarian utopia.

Education, religion and currency were abolished, and the country’s entire population was put to work in vast collective farms.

This radical social-engineering experiment, however, quickly became one of the 20th century’s worst tragedies, with an estimated 1.7 million Cambodians dying of disease, exhaustion from overwork, torture or execution.

During a six-month trial last year – the tribunal’s first – prosecutors painted Duch, a 67 year-old former math teacher, as a driving force behind the regime’s execution campaign, and argued that he guided crimes committed at Tuol Sleng.

Duch’s defence, on the other hand, contended that he had merely carried out orders issued by his superiors with an eye towards ensuring his own survival.

His lawyers also stressed the fact that Duch, a converted Christian, is the only suspect held by the tribunal to have confessed and expressed remorse for crimes committed during the regime years.

This tactic, however, was undermined during closing arguments last November, when Duch, who had earlier told judges he would be willing to submit himself to a public stoning, asked instead to be acquitted and released.

In the run-up to the verdict, he fired his international co-lawyer, who appeared to have been the architect of his bid for a mitigated sentence. This move prompted observers to speculate that Duch will mount a vigorous appeal.

Five former Khmer Rouge leaders, including Duch, have been detained so far by the tribunal. The court now moves on to Case 002, for which the remaining four regime leaders are awaiting a trial expected to begin some time next year.