A man suffered serious head injuries when he tackled a gang of masked robbers who had smashed their way into a Cambridgeshire pub.
The five men, armed with weapons and wearing balaclavas, broke into the Boathouse pub, Thorpe Meadows in Peterborough on Monday at 0330 BST.
The gang confronted the bar manager, hitting him around the head before escaping with several thousand pounds.
It is believed one of the offenders also suffered a head injury.
Another member of staff was also threatened by the gang during the robbery.
The injured bar manager was taken to Peterborough District Hospital with serious, but not life-threatening, injuries.
Det Sgt James Weston said: "This appears to be a planned robbery and must have been an terrifying ordeal for the victims.
"It is possible one of the offenders is likely to have sustained a visible head injury during the incident.
"I would appeal to anyone who has any information about the robbery or those responsible to contact police."