PHNOM PENH - The Khmer Rouge's executioner-in-chief, the prison boss allegedly responsible for the torture and murder of more than 12,000 people, has made a final plea before an international court, asking that he be allowed to meet his victims' families to apologise in person.

This picture taken and released by the Extraordinary Chamber in the Courts of Cambodia (ECCC), shows former Khmer Rouge chief of "S-21", known as Tuol Sleng prison, Kaing Guek Eav, alias Duch (centre), standing in the courtroom at the Extraodinary Chambers in the Courts of Cambodia in Phnom Penh. Prosecutors have asked Cambodia's war crimes court to hand Duch a 40-year jail term. (AFP/HO) Kaing Guek Eav, known as Comrade Duch, told the Extraordinary Chamber of the Courts of Cambodia in Phnom Penh yesterday that he took full responsibility for the torture and the murders that occurred at his prison.

"I am solely and individually responsible for the loss of at least 12,380 lives,'' he said. ''These people before their deaths have endured great and prolonged suffering and countless indignities. I still and forever wish most respectful and humble apologies to the dead souls.

"As for the families, I [am] asking you to kindly leave your door open for me to make my apologies. May I meet with you to allow me to share your intense and enduring sorrow any time in order to express my most excruciating remorse."

But, dressed in a carefully ironed blue shirt, the bespectacled former high-school mathematics teacher spoke calmly and coldly, his evidence littered with casual references to people being "smashed" and "the wishes of the party".

For Cambodians, the controversial tribunal, established in 2006 after nearly a decade of negotiations between Cambodia and the United Nations, is the last chance to find justice for the Khmer Rouge's crimes.

As head of Tuol Sleng prison, a converted high school also known as S-21, Duch explained his role was to "smash" people presumed disloyal to the Khmer Rouge movement.

Every prisoner was assumed guilty, he explained, effectively "already dead". They were tortured for false confessions, usually that they were CIA or KGB traitors, through electric shocks, beatings and whippings, water-boarding, having fingers cut off or toenails pulled out. They were then executed, most driven to nearby Choeung Ek - the Killing Fields - where they were bludgeoned to death with ox-cart axles and buried in mass graves.

"Those people were the innocent, the clean, the very honest," Duch admitted yesterday. "I don't believe they had committed any wrongdoing, as they were accused."

Speaking from a handwritten speech, which ran to more than 10 pages, Duch said he found himself unwittingly caught up in a revolution he came to despise, and was forced to do his job at Tuol Sleng against his wishes, out of fear he would be killed if he refused.

"I could not withdraw from it ... I am very terrified."

But the apology, broadcast live on national TV, left many Cambodians cold. Norng Charnpal, one of only a dozen people to have walked out of Tuol Sleng alive, told The Age he did not want Duch to apologise.

"I don't want to hear this. It is not real and it is not enough for my family," he said.

Earlier in the day, prosecutors asked that Duch be jailed for 40 years for his crimes, effectively a life sentence for the 65-year-old. He will be sentenced next year. Lead prosecutor, Australian William Smith, rejected Duch's claim he was acting only out of fear for his own life, telling the court: "The accused was neither a prisoner, nor a hostage, nor a victim.

"He was an idealist, a revolutionary, a crusader ... prepared to torture and kill willingly for the good of the revolution."

Throughout the trial, Duch has listened, attentively but impassively, as the evidence of the murderous regime he oversaw is laid bare before the court.

Even as the court heard this week of his orders that inmates who soil themselves be forced to eat their excreta, Duch has appeared inscrutable, simply taking meticulous notes of all that is said.

The Khmer Rouge ruled Cambodia for four years between 1975 and 1979. The ultra-communist regime killed, through starvation, overwork, disease and murder, an estimated 1.7 million people, one-quarter of the population.

Duch has been detained since 1999, when he was found working as a Christian aid worker in the jungle, and was formally arrested by the tribunal in July 2007.