By Tim Hanlon A manhunt is underway for masked motorcycle riders who ambushed two victims and stabbed one in the torso before fleeing the scene. Police are appealing to the public for information as they try and track down the two masked bikers who left a man in a serious condition and had to remain in hospital overnight following the attack on Saturday. One of the victims had his pockets searched by the riders and then the second was stabbed in the torso after they were ambushed in the incident that took place in the evening. Police said that the attack took place in Watford, Hertfordshire, a…