DAVE Wilson had the shock of his life when he was digging in his back garden in Trough Lane, Bovey Tracey, on Sunday.
His spade struck what he thought was a stone, but when he investigated he discovered it was an unexploded hand grenade.
The 54-year-old alerted the police and made sure his wife and son Harry were safely away from the device.
PC Simon Grost, who attended along with colleague PC Anthony Brodest, said they inspected the device, immediately informed the Royal Navy Bomb Disposal Unit, Plymouth, and put a 100-metre diameter cordon around the area.
That involved evacuating two families from the adjoining Devon House, and sealing off the road.
'Mr Wilson and his family were able to go into a deep cellar in their home,' said PC Grost.
He added that churchgoers at the nearby parish church were notified of the situation, but the morning service had gone ahead as normal because the church was just outside the cordon.
On arrival the bomb disposal team confirmed it was a live world war two hand grenade.
'They placed it in a bomb proof container and took it to a field 100 metres away where it was detonated in a controlled explosion.
'It was a significant explosion. I was taking cover behind the van some 100 metres away and stones came flying over. The explosion, at about 12.55pm, was heard right through the town,' said PC Grost.
'I gather that according to locals Devon House was used by American officers during the second world war and some ordnance was buried in the field adjacent.
'If anyone does find any devices they should let us know immediately,' said PC Grost.
Petty Officer Jim Diamond, part of the RN Bomb Disposal Team, said: 'This was a straightforward job dealing with a world war two hand grenade which could have been a hazard to the public. The member of the public who raised the alarm did the correct thing to call in the experts.
'We always advise people who think they have found something that looks like it could be an explosive not to handle it themselves.'