London police say they have detained a man after a vehicle mounted the curb near the Natural History Museum on Saturday, leaving nearly a dozen pedestrians injured. Police say the man has not been charged and the incident was a traffic accident, not a terror attack. The London Ambulance Service said 11 people were injured and nine of them taken to a hospital to be treated, mostly for leg and head injuries. The accident initially triggered a massive police response, with witnesses at the scene describing helicopters hovering overhead as paramedics tended to the injured. Britain is on a “severe” terrorist threat level, meaning attacks are likely.