"We needed a fightback and a fightback is under way", the Prime Minister has said after four days of riots.David Cameron said every action would be taken to restore order, with contingency plans for water cannon to be available at 24 hours' notice.On Tuesday night, unrest spread to cities including Manchester, Salford, Liverpool, Nottingham and Birmingham, with shops being looted and set alight.Three men died when they were hit by a car in Birmingham.Mr Cameron, speaking after a meeting of the government's Cobra emergency committee said police were authorised to take "any action necessary" to bring the situation under control.He said: "This continued violence is simply not acceptable, and it will be stopped. We will not put up with this in our country. We will not allow a culture of fear to...