Fishermen had to call in bomb squad divers after they realised part of their catch was an unexploded three-quarter-ton German mine.
And they watched as plumes of water erupted into the air after the Second World War charge was blown up on the seabed.
Royal Navy frogmen from the Portsmouth area clearance diving unit scrambled to the Lymington trawler Coriolus in Freshwater Bay, off the Isle of Wight.
They looped ropes around the 9ft charge and lowered it over the side of the boat and back down to the seabed 15 metres below.
Once there, divers planted explosives on the mine and coastguards cleared the area as it was detonated.
Divers’ leader Lieutenant Ian Morton said the blast was classified as high order – ‘a big bang’.