Zakaria Amara was convicted of participating in a terrorist group and intending to cause an explosion for the benefit of a terrorist group. (Reuters)

The convicted mastermind behind a plot to cause death and destruction in downtown Toronto, says he is a changed man but one who deserves Canadians' contempt for his former extremism.

Zakaria Amara, a co-leader of the Toronto 18 plot to set off bombs in Toronto and at a military base in Ontario, pleaded guilty in October.

At his sentencing hearing in Brampton, Amara read a letter to the judge and an open letter to "fellow Canadians."

"I am certain that many, if not all of you, will never forgive me for my actions," Amara wrote in his letter to Canadians. "I have no excuses or explanations. I deserve nothing less than your complete and absolute contempt."

In his letter to the judge, Amara wrote that his struggle for the truth led to his extremism, but during the last several months in prison he came to see how wrong he was.

"I promise that no matter how long it takes and how much it costs that I will produce actions that will hopefully outweigh the actions that I once took towards hurting others," he said.

"Give me a chance that one day I will be able to pay the moral debt I still owe."

Amara's wife also wrote a letter to the judge, talking about how, because of her husband's "enormous mistake," she and their four-year-old daughter are paying a heavy price.

Amara sobbed, buried his face in his hands, wiped tears from his face, then rested his head on his knees as his wife's letter was read aloud by his lawyer. She wrote she is living in her parents' basement and going to school in the hopes of providing a future for their daughter, who prays every night for her dad to come home.

'Naive and gullible'

Amara was among 17 men and youths who were arrested in the Toronto area and detained in June 2006 after an investigation by CSIS. An 18th person was arrested that August.

Amara told the court he had been "naive and gullible" and had a simplistic way of viewing the world. He said that he was locked into an extremist position that caused him to isolate himself from the real world.

He said that he was glad he was arrested before he could do any harm and that he gradually changed in prison.

But spending three years in solitary confinement after his arrest was "the antithesis of rehabilitation, since it directly served the demands of my ideology."

He didn't really begin to change until he was allowed to mingle with other inmates at the prison and was able to discuss "the justification of terrorist acts," he said.

"I was exposed to types of people that I never had a real interaction with when I was free."

One inmate, who had the greatest influence on Amara's changed outlook, used to work on Bay Street, Amara said, adding the inmate's brothers worked in the Exchange Tower — a building Amara had plotted to blow up.

"Despite these facts, he looked after me the most," Amara said. "He always counselled me about my situation and how to turn it around."

Amara also spoke positively of the time he spent with a Jewish inmate.

"He once told me that had we been living in Palestine, we would have probably killed each other and died failing to realize what good friends we would have made if only we had talked."

To Muslims in particular, Amara said he can't imagine the embarrassment suffered in the days after his arrest. The gravity of what he did "makes any excuse or apology inappropriate."

The Crown is seeking a life sentence, while the defence is seeking a sentence of 18 to 20 years.

Three other people in the plot have pleaded guilty. A youth was also found guilty, seven people had their charges dropped or stayed, one man is currently before the courts and five others await trial.

With files from The Canadian Press