She protected my wife from an aggressive Mastiff yesterday by running forward about twenty metres in front of her and straight at the Mastiff, shifting side on and moving so the Mastiff couldn't get close. The owner of the Mastiff, who had rescued it the day before and knew that it was aggressive to people, apologised for having it off the lead, saying that she didn't think anyone would be around. When will people learn? Dogs should be on lead until such time as you have established trust and control.