A police officer in the upper left part of this image appears to be coming from across the street in the direction of the alleged victim. (CBC)

A grainy surveillance tape released by the lawyer of a man allegedly assaulted by a Vancouver policeman shows an officer crossing a street and cross-checking a man with his baton, knocking him down.

Sgt. Darcy Taylor has been charged with assault with a weapon following the incident in August 2009.

The alleged victim's lawyer said his client did nothing to provoke the action by the officer.

"You can see my client, he's got his hands in his pocket, fiddling with his cellphone," Jason Tarnow said as he showed the tape to CBC News on Wednesday.

A 27-year-old man laid a complaint about one month after the incident and the charge against Taylor — a 20-year veteran of the force — was made public by Vancouver police Insp. Mario Giardini at a news conference Monday.

Not seriously injured

Giardini said police were called to the scene outside the Regal Beagle restaurant on West Broadway in the early morning hours of Aug. 23 following a report of a fight.

No fight is visible on the tape and it appeared that the officer came across the street before striking a man with his baton, which buckled the man over as he falls down.

A man buckles over after apparently being struck by the officer's baton. (CBC)

The man — whose identity has not been made public — was not seriously injured in the incident.

"He did nothing at all to deserve the abuse that was directed toward him," said Tarnow.

The video shows the officer was overzealous and dangerous, said the lawyer.

"He was being a bully. He was out of control," Tarnow said.

Tape likely crucial

The lawyer said the tape likely proved crucial in the investigation of the complaint.

"I don't think there would be charges against this senior officer if there wasn't video of the incident."

Police would not comment Wednesday after the tape was released.

"It's very tough for everybody in the department," Giardini said Monday, in reference to the Crown's decision to charge Taylor.

The officer has been reassigned to desk duties and is scheduled to appear in court Jan. 13.