A London, Ont., doctor said he didn't go to police after a 2010 meeting with two men who were allegedly discussing terrorism plans because he didn't think the plot was serious.

But Dr. Khurram Sher conceded to prosecutors in an Ottawa courtroom on Friday that "in retrospect" the plot was serious and that he wished he had gone to police.

Sher, a former pathologist who lived in London, Ont., is charged with conspiring to knowingly facilitate a terrorist activity.

Khurram Sher

Khurram Sher, right, is facing a charge of conspiring to knowingly facilitate a terrorist activity. (CBC)

The trial is mostly focused on a late-night meeting at an Ottawa townhouse on July 20, 2010 involving Sher and two other men.

According to wiretap transcripts of the meeting, the three discuss sending money to the Taliban, travelling to Pakistan to get military training, forming a group and electing a leader from among the three of them.

They also talk briefly about bomb making, and appear to discuss a potential target: CFB Trenton in Ontario, the base where the bodies of Canadian soldiers killed in Afghanistan are repatriated.

In previous testimony, Sher said he was invited to the meeting by a longtime friend and that he did not know the other man.

Sher said he was playing along to learn more

He said he was surprised his friend would be involved in such a meeting, but admitted under cross-examination Friday he never attempted to dissuade his friend after the meeting.

Crown lawyers expressed disbelief when Sher intimated that he said nothing at the meeting because he was playing along to learn more.

"So you were acting as an undercover police officer?" asked Crown attorney Jason Wakely.

Sher said he regretted not speaking out, both to the two men during the meeting but also to police afterwards and told the court the incident and his subsequent arrest has cost him his house and his career.

The trial resumes next week.