The APEC inquiry is hearing some long-awaited testimony as RCMP Staff Sgt. Hugh Stewart appears before the commission to tell his side of the story.

Stewart is now a familiar face. He was the Mountie who was captured on video spraying a can of pepper spray at student protesters on Nov. 25, 1997. For his actions, demonstrators dubbed the veteran officer, "Sgt. Pepper."

Monday was the first time Stewart has testified at the inquiry that's investigating how the RCMP handled security at the 1997 summit at the University of British Columbia in Vancouver.

One of the inquiry's key questions is whether the use of pepper spray was justified. Lawyers for the protesters want to know why police cracked down on a peaceful protest.

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Monday, Stewart tried to explain to the inquiry exactly what happened that day. He says he was ordered to clear the road at UBC because the summit leaders were in a rush to leave the grounds. He was told he had only about six minutes to get rid of the protesters who were occupying the only route off the campus.

Stewart admitted that at the now-famous protest at Gate 6, he gave protesters only a few seconds to respond to his order to clear the road before dousing them with pepper spray.

Why didn't he give them more of a chance to move? Stewart says it appeared to him that the demonstrators had no intention of leaving. Three protesters in front of him began locking arms so they could not be dragged off the road, he said. Others began moving facial coverings in a way he interpreted as aimed at thwarting the spray.

"I realized they had taken definitive action and I realized I had to respond in kind and I stepped up one level, and used spray," Stewart told the inquiry.

But the commission's lawyer said he's studied all the video footage, and all the photographs from that scene and he can't find any evidence of people locking arms.

Stewart's testimony is expected to last at least four days. The inquiry itself is slated to run well into next year. The reports from Commissioner Ted Hughes could come months after that.