A German First World War hand grenade was found in a shipment of French potatoes imported for a Hong Kong crisp factory.
The bomb, measuring 8cm (3ins) wide and weighing about 1kg (2lb), was blown up in a controlled explosion following its discovery at the Calbee snack making plant.
A police video showed bomb disposal officers packing the grenade in a drainage channel at the site before detonating it.
Superintendent Wilfred Wong Ho-hon said: “The grenade was in an unstable condition because it has been previously discharged but failed to detonate.
“All the information to date suggested that the grenade was imported from France together with the other potatoes.”
The grenade is believed to have been left in a trench during the First World War and accidentally gathered up with potatoes harvested a century later in the former battlefield.
“If it was covered in mud, the grenade was likely to have been left behind, dropped by soldiers there during the war, or left there after it was thrown,” Hong Kong University military historian Dave Macri told the South China Morning Post.
“The ditch was then filled up and used as a growing field, and the explosive was tossed into the mix of harvested potatoes… and sent to Hong Kong.”
Hong Kong police are used to dealing with unexploded wartime bombs.
Old munitions are often found by walkers or construction workers in the southern Chinese city, which was the scene of fierce fighting between Japanese and allied British forces in 1941.
The then-British colony was heavily bombed by US and allied forces after the city fell to the invading Japanese.
(c) Sky News 2019: WWI hand grenade found in French potato cargo for crisp factory