Several roads have been closed by police after reports a collision involving a bus and at least three cars.Charlestown Road in Blackley is closed in both directions between Grange Park Road and Booth Hall Road due to a road traffic collision, Transport for Greater Manchester said in a tweet.Pictures from the scene showed a number of damaged cars including a black Audi Q7.Eyewitness Robert Duck told the M.E.N: "The Audi tried to overtake a bus at speed, it hit the back of the bus and then hit