A family-friendly charity fun day ended with the arrival of a bomb squad after a Second World War grenade was discovered.
The metal-detecting event at Thurland Castle near Tunstall, Lancashire, descended into chaos when the highly explosive weapon was unearthed.
Cheshire Police’s bomb disposal team rushed to the castle to diffuse the cast iron 36 Mk I grenade, also known as a ‘Mills bomb’.
A 330-foot (100m) cordon had to be erected around the site due to fears the 70g TNT device could explode.
William Hargreaves, the chairman of the Lune Valley Metal Detecting Club which ran the event, said: ‘We do like our events to end with a bang but loud explosions are not what we normally have in mind.’
Find came a couple hours in the event at the 13th century castle.
More than 60 people young and old were searching for treasure on the castle’s back fields, raising £400 for a local charity.
After picking up a number of Roman artefacts and Elizabethan coins, one detectorist stumbled upon the grenade at 11am last Sunday.
Police then dispatched a bomb disposal unit to the castle, who confirmed the grenade to be dangerous at 2.30pm.
The wartime relic was buried eight inches under the ground.
All participants had to leave the area before a massive bang ricocheted across the castle grounds and shook nearby windows.
John Ferguson, 82, a veteran committee member, said: ‘It was found without a pin in it meaning it could have been defective – but we assumed it was still live.
‘If it had gone off it could have killed the person who found it – it sends shrapnel flying 30 meters as it was on a mushy surface.’
‘It was reported to the police, who demanded the site be cleared of all detectorists.’
The 36 Mk I Grenade was introduced at the end of the First World War and remained the standard British fragmentation grenade until 1972.
It was also used by Australian and other Commonwealth forces.
The weapon’s segmented body means it breaks into even pieces when it explodes.
This is not the first time this year that an unexploded Second World War bomb wreaked havoc.
All Eurostar trains from London to Paris were cancelled at the beginning of March following the discovery of an unexploded device on railway tracks.
Just days later, rail services were suspended, roads were closed and people were urged to avoid the area after an explosive device was found in New Brighton, Merseyside.
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