This is the moment a wartime bomb exploded suddenly while experts tried to defuse the device.
A major incident was declared following the discovery of the bomb at a river crossing in Great Yarmouth, Norfolk, on Tuesday.
Since then, emergency services and agencies worked to disarm the device - with homes and businesses evacuated to keep residents safe.
Yesterday afternoon, Norfolk Police confirmed there was an "unplanned" detonation - but added that no one was hurt when the bomb exploded.
A police drone captured the dramatic moment the bomb detonated, sending thick plumes of smoke into the air.
Norfolk Police published a clip of the explosion on Twitter, saying: "The unexploded bomb in #GreatYarmouth detonated earlier during work to disarm it. Our drone captured the moment.
"We can confirm that no one was injured. Public safety has been at the heart of our decision making all the way through this operation, which we know has been lengthy."
Police added: "Both 400m & 200m cordons have lifted with most roads reopened in those locations. Southtown Road remains closed while necessary checks on damage take place.
"People can return to their homes. The Local Resilience Forum have confirmed they’ve stood the major incident response down."
Army specialists had been cutting the bomb using a technique which creates a slow burn of the explosives, and burns off that material.
Officers had said there was a risk of an unintended detonation.
After the explosion, the force said on Twitter: "We can confirm the unexploded World War II bomb in Great Yarmouth has detonated.
"This was not a planned detonation & happened during slow burn work to disarm the explosives.
"All army & emergency service personnel are accounted for. We will bring you further info when we have it."
The work to cut into it began on Thursday, but the water needed to do the work reduced the effectiveness of the sand barrier around the device.
The device is about one-metre (3.2ft) long and weighs about 250kg (39st 5lbs) - and was discovered by a contractor working on the third crossing over the River Yare.
There had been a 400-metre cordon at the scene.
Norfolk Constabulary's Assistant Chief Constable Nick Davison said: "This has been a painstakingly long process but public safety and that of the people involved in the operation has been at the heart of decision making.
"This was the final phase of a delicate operation which has caused much disruption in the town, but we're hopeful this could be resolved soon and that cordons can be lifted, if everything goes to plan."
A spokesperson for Cadent, which manages the local gas mains network, said: "Our team has carried out a close inspection of our pipes in the vicinity.
"There is no indication that the blast has caused damage to our assets and gas continues to flow safely."
