A British Columbia Supreme Court judge has thrown out marijuana trafficking charges against a man after the Surrey RCMP drug squad rammed down the door of his garage and entered guns drawn.

Police had a search warrant when they knocked on Van Dung Cao's front door in March 2004, while another team bashed down a garage door and entered with their guns out.

Officers found more than 700 marijuana plants in the basement, but they won't be able to use that evidence against the man because the judge has ruled it inadmissible.

Justice Catherine Bruce ruled the RCMP team violated the knock and announce rule, giving the person inside the home enough time to answer the door before police move in.

"While the police knocked and announced at the front door, there was no announcement at the garage door before the garage door was battered down and entry secured," Bruce wrote in her ruling.

"The actions of the police created a real risk of harm to an occupant by accidental shooting and to the police in terms of an aggressive response to the violent entry," she said.

"In my view, a shocking entry without a prior knock and announce, with guns drawn and ready to be discharged, and pointed at the accused's head, could have produced disastrous consequences."

Bruce also said police had other alternatives that did not involve a breach of Cao's charter rights.