Police had to close part of the A6 in Northamptonshire after two brothers found a live grenade in the River Nene.
Stevie Potter, 26, and his 32-year-old sibling James Mcintyre were magnet fishing under the bridge between Irthlingborough and Higham Ferrers earlier today when they pulled out the explosive.
After hooking the item out of the water, Stevie didn't realise what it was until he noticed the ridges on the grenade.
"We didn't know what it was at the time, it looked like a rock," said Stevie, a smart repair technician from Ringstead.
"I was shaking, I didn't know if it was going to go off.
"We called the police and they came within five minutes."
Tactical support officers were on the scene and Station Road was taped off as was the A6 from the B5348 roundabout down to the A45 roundabout.
An EOD (Explosive Ordnance Disposal) unit also attended.