Eric Lombard, the head of the bomb disposal squad of the Sécurité Civile, the French civil defence force, said it intervened two or three times each week to dispose of unexploded ordnance brought up by “magnet fishers”.
It is being called out increasingly often as the practice gains popularity, he added.
The French government has issued new advice reminding local authorities that magnet fishing is illegal, although offenders are generally cautioned rather than being fined. It is particularly concerned about the Somme, in northern France, where there are many unexploded shells from the First World War.
According to civil defence officials, there is so much unexploded ordnance in France from the First and Second World Wars that it would take “three centuries” to remove it all.
“You can find all types of ammunition in bodies of water, mainly grenades, artillery shells or mortar bombs, anti-tank and anti-personnel mines, so there are fears of explosions or the malicious use of this ordnance,” Commander Lombard said.