The bomb was about a meter long and weighed about 250 kilograms. She was discovered by a contractor on Tuesday while working near the River Yare in the town in Norfolk, east England.
Preparations for the detonation of the bomb began on Thursday. Specialists tried to dismantle the explosive using a method involving the risk of explosion. The Norfolk police chief tells the BBC that this was nevertheless the safest approach. A safety zone of 400 meters was set up around the bomb.