A “reckless” man prompted a full-scale response from the emergency services after jumping from Wisbech Town Bridge into the river for a joke.
The police helicopter and officers were scrambled to the town centre bridge on Saturday evening after a drunk man decided to leap into the River Nene.
Firefighters and paramedics were also called to the scene to help the man, who was arrested and later released without charge by police officers.
Fenland’s Insp Will Davis said the man had endangered officers.
He said: “His actions were incredibly reckless and put not only his life in danger but those who would try to come to his aid.
“The male thought the whole thing was a joke and failed to see the seriousness and consequences of his actions.”
The man was spotted on the town bridge by a Fenland CCTV operator at 11.45pm on January 30 and raised the alarm.
Firefighters, ambulance crews, the harbour master and the police helicopter were called to the late night incident.