London: A man armed with a knife was arrested after climbing a fence behind British Prime Minister Tony Blair's London residence at 10 Downing Street, police said on Monday. The man breached the security cordon behind the residence near the Horse Guards Parade late Sunday, Scotland Yard told CNN. After a brief struggle with police officers, he was arrested was taken to a central London police station for further questioning. Blair was home at the time of the incident but police said his safety was not threatened. "As he got to the other side he was immediately challenged by an officer and arrested following a short struggle," a police spokesman told Reuters. "We are satisfied that at no time the Prime Minister was at risk," he added. There was no comment from Blair's office.