The men were crushed when the coach lurched through a missile-hurling crowd at the Meadowcroft greyhound racing stadium at Stainforth, Doncaster, South Yorkshire, after a "serious disturbance" inside.
In an attempt to escape, some people boarded the waiting coach which was then surrounded by an angry mob and pelted with missiles, including beer barrels, bottles and bricks.
Fighting first broke out in a bar at the stadium as about 35 men on a stag night from Scunthorpe confronted others from Doncaster, towns with a history of rivalry.
Detective Superintendent Les Agar said the Scunthorpe party arrived at the stadium at about 7pm and went for a drink at the King George pub opposite. They returned at 10pm but there was no trouble until closing time when a fight broke out in an upstairs bar between a man from Scunthorpe and a "local".
"This was momentarily broken up by security staff who were then confronted by a large group of the Scunthorpe party armed with bottles," Mr Agar said.
"The melee continued as the group was forced into the car park. As the Scunthorpe contingent were trying to get on the coach, empty 45-gallon drums, bricks and bottles were thrown at it. Several windows were smashed on both sides and, as the bus pulled away still under attack, the driver was forced to reverse to get out.
"One unconscious man had to be dragged from the path of the coach as it was reversing. It was when the vehicle lurched forward again that the two men, standing close together, were hit."
Police named the dead men as Phillip Hodson, 29, of Dryden Road, Scunthorpe, who was married with two children, and Stephen Millhouse Jaksics, 35, of Hempdyke Road, also in Scunthorpe.
The coach driver, who was said to be "deeply shocked", was questioned by police for two hours but not charged. He was released on police bail. Inquiries are continuing.Reuse content