John Harvey bravely intervened after a gang of 12 yobs started vandalising a cricket club where he works in Tunbridge Wells, Kent, and grabbed the main culprit.
The groundsman at Linden Park Cricket Club called police as he held the teenager telling cops he had caught the yob in the act and they should send an officer to arrest the teen.
But as the 47-year-old was desperately trying to keep hold of the teen as the other yobs - armed with sticks surrounded him - the police operator warned him he could be charged with assault.
Mr Harvey said: "I expected to be thoroughly supported by the police as a civilian and not rebuked.
"I was expecting a response car immediately. I had restrained someone in the act of vandalism and she said 'I must warn you, you are leaving yourself open to an assault charge'." Read more